The NTLM Authentication Protocol and Security Support Provider

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The NTLM Authentication Protocol and Security Support Provider

Abstract

This article seeks to describe the NTLM authentication protocol and related security support provider functionality at an intermediate to advanced level of detail, suitable as a reference for implementors. It is hoped that this document will evolve into a comprehensive description of NTLM; at this time there are omissions, both in the author's knowledge and in his documentation, and almost certainly inaccuracies. However, this document should at least be able to provide a solid foundation for further research. The information presented herein was used as the basis for the implementation of NTLM authentication in the open-source jCIFS library, available at http://jcifs.samba.org. This documentation is based on independent research by the author and analysis of functionality implemented in the Samba software suite.

What is NTLM?
NTLM Terminology
The NTLM Message Header Layout
- The NTLM Flags
The Type 1 Message
- Type 1 Message Example
The Type 2 Message
- Type 2 Message Example
The Type 3 Message
- Name Variations
- Responding to the Challenge
  - The LM Response
  - The NTLM Response
  - The NTLMv2 Response
  - The LMv2 Response
  - The NTLM2 Session Response
  - The Anonymous Response
- Type 3 Message Example
NTLM Version 2
NTLMSSP and SSPI
- Local Authentication
- Datagram Authentication
Session Security - Signing & Sealing Concepts
- The User Session Key
  - The LM User Session Key
  - The NTLM User Session Key
  - The LMv2 User Session Key
  - The NTLMv2 User Session Key
  - The NTLM2 Session Response User Session Key
  - The Null User Session Key
- The Lan Manager Session Key
- Key Exchange
- Key Weakening
NTLM1 Session Security
- NTLM1 Key Derivation
  - Master Key Negotiation
  - Key Exchange
  - Key Weakening
- Signing
- Sealing
NTLM2 Session Security
- NTLM2 Key Derivation
  - Master Key Negotiation
  - Key Exchange
  - Key Weakening
  - Subkey Generation
- Signing
- Sealing
Miscellaneous Session Security Topics
- Datagram Signing & Sealing
- "Dummy" Signing
Appendix A: Links and References
Appendix B: Application Protocol Usage of NTLM
- NTLM HTTP Authentication
- NTLM POP3 Authentication
- NTLM IMAP Authentication
- NTLM SMTP Authentication
Appendix C: Sample NTLMSSP Operation Decompositions
- NTLMv1 Authentication; NTLM1 Signing and Sealing Using the NTLM User Session Key
- NTLMv1 Authentication; NTLM1 Signing and Sealing Using the LM User Session Key
- NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 56-bit Lan Manager Session Key
- NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key
- NTLMv1 Datagram-Style Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key With Key Exchange Negotiated
- NTLMv1 Authentication; NTLM1 "Dummy" Signing and Sealing Using the NTLM User Session Key
- NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 128-bit NTLM2 Session Response User Session Key With Key Exchange Negotiated
- NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 40-bit NTLM2 Session Response User Session Key
- NTLMv2 Authentication; NTLM1 Signing and Sealing Using the 40-bit NTLMv2 User Session Key
- NTLMv2 Authentication; NTLM2 Signing and Sealing Using the 56-bit NTLMv2 User Session Key
- Anonymous NTLMv1 Authentication; NTLM2 Signing and Sealing Using the 128-bit Null User Session Key With Key Exchange Negotiated
- Local NTLMv1 Authentication; NTLM2 Signing and Sealing Using an Unknown Session Key With Key Exchange Negotiated (Analysis Incomplete)
Appendix D: Java Implementation of the Type 3 Response Calculations

What is NTLM?
NTLM is a suite of authentication and session security protocols used in various Microsoft network protocol implementations and supported by the NTLM Security Support Provider ("NTLMSSP"). Originally used for authentication and negotiation of secure DCE/RPC, NTLM is also used throughout Microsoft's systems as an integrated single sign-on mechanism. It is probably best recognized as part of the "Integrated Windows Authentication" stack for HTTP authentication; however, it is also used in Microsoft implementations of SMTP, POP3, IMAP (all part of Exchange), CIFS/SMB, Telnet, SIP, and possibly others.
The NTLM Security Support Provider provides authentication, integrity, and confidentiality services within the Window Security Support Provider Interface (SSPI) framework. SSPI specifies a core set of security functionality that is implemented by supporting providers; the NTLMSSP is such a provider. The SSPI specifies, and the NTLMSSP implements, the following core operations:
1. Authentication -- NTLM provides a challenge-response authentication mechanism, in which clients are able to prove their identities without sending a password to the server.
2. Signing -- The NTLMSSP provides a means of applying a digital "signature" to a message. This ensures that the signed message has not been modified (either accidentally or intentionally) and that that signing party has knowledge of a shared secret. NTLM implements a symmetric signature scheme (Message Authentication Code, or MAC); that is, a valid signature can only be generated and verified by parties that possess the common shared key.
3. Sealing -- The NTLMSSP implements a symmetric-key encryption mechanism, which provides message confidentiality. In the case of NTLM, sealing also implies signing (a signed message is not necessarily sealed, but all sealed messages are signed).
NTLM has been largely supplanted by Kerberos as the authentication protocol of choice for domain-based scenarios. However, Kerberos is a trusted-third-party scheme, and cannot be used in situations where no trusted third party exists; for example, member servers (servers that are not part of a domain), local accounts, and authentication to resources in an untrusted domain. In such scenarios, NTLM continues to be the primary authentication mechanism (and likely will be for a long time).
NTLM Terminology
Before we start digging in any further, we will need to define a few terms used in the various protocols.
NTLM authentication is a challenge-response scheme, consisting of three messages, commonly referred to as Type 1 (negotiation), Type 2 (challenge) and Type 3 (authentication). It basically works like this:
1. The client sends a Type 1 message to the server. This primarily contains a list of features supported by the client and requested of the server.
2. The server responds with a Type 2 message. This contains a list of features supported and agreed upon by the server. Most importantly, however, it contains a challenge generated by the server.
3. The client replies to the challenge with a Type 3 message. This contains several pieces of information about the client, including the domain and username of the client user. It also contains one or more responses to the Type 2 challenge.
The responses in the Type 3 message are the most critical piece, as they prove to the server that the client user has knowledge of the account password.
The process of authentication establishes a shared context between the two involved parties; this includes a shared session key, used for subsequent signing and sealing operations.
In this document, to avoid confusion (as much as possible, anyway) the following convention will be observed:
- When discussing authentication, the protocol version will use "v-numbering"; for example, "NTLMv1 Authentication".
- When discussing session security (signing & sealing), the "v" will be omitted; for example, "NTLM1 Session Security".
This should keep things fairly clear, except for the possibly awkward case of "NTLM2 Session Response" authentication (a variant of NTLMv1 authentication that is used in conjunction with NTLM2 session security). Hopefully by the time we get there this will all make much more sense.
For our purposes, a "short" is a little-endian, 16-bit unsigned value. For example, the decimal value "1234" represented as a short would be physically laid out as "0xd204" in hexadecimal.
A "long" is a little-endian, 32-bit unsigned value. The decimal value "1234" represented as a long in hexidecimal would be "0xd2040000".
A Unicode string is a string in which each character is represented as a 16-bit little-endian value (16-bit UCS-2 Transformation Format, little-endian byte order, with no Byte Order Mark and no null-terminator). The string "hello" in Unicode would be represented hexidecimally as "0x680065006c006c006f00".
An OEM string is a string in which each character is represented as an 8-bit value from the local machine's native character set (DOS codepage). There is no null-terminator. In NTLM messages, OEM strings are typically presented in uppercase. The string "HELLO" in OEM would be represented hexidecimally as "0x48454c4c4f".
A "security buffer" is a structure used to point to a buffer of binary data. It consists of:
1. A short containing the length of the buffer content in bytes (may be zero).
2. A short containing the allocated space for the buffer in bytes (greater than or equal to the length; typically the same as the length).
3. A long containing the offset to the start of the buffer in bytes (from the beginning of the NTLM message).
So the security buffer "0xd204d204e1100000" would be read as:
Length: 0xd204 (1234 bytes)
Allocated Space: 0xd204 (1234 bytes)
Offset: 0xe1100000 (4321 bytes)
If you started at the first byte in the message, and skipped ahead 4321 bytes, you would be at the start of the data buffer. You would read 1234 bytes (which is the length of the buffer). Since the allocated space for the buffer is also 1234 bytes, you would then be at the end of the buffer.
The NTLM Message Header Layout
Now we're ready to look at the physical layout of NTLM authentication message headers.
All messages start with the NTLMSSP signature, which is (aptly enough) the null-terminated ASCII string "NTLMSSP" (hexadecimal "0x4e544c4d53535000").
Next is a long containing the message type (1, 2, or 3). A Type 1 message, for example, has type "0x01000000" in hex.
This is followed by message-specific information, typically consisting of security buffers and the message flags.
The NTLM Flags
The message flags are contained in a bitfield within the header. This is a long, in which each bit represents a specific flag. Most of these will make more sense later, but we'll go ahead and present them here to establish a frame of reference for the rest of the discussion. Flags marked as "unidentified" or "unknown" in the table below are outside the realm of the author's knowledge (which is not by any means absolute).
FlagNameDescription0x00000001Negotiate UnicodeIndicates that Unicode strings are supported for use in security buffer data. 0x00000002Negotiate OEMIndicates that OEM strings are supported for use in security buffer data. 0x00000004Request TargetRequests that the server's authentication realm be included in the Type 2 message. 0x00000008unknownThis flag's usage has not been identified. 0x00000010Negotiate SignSpecifies that authenticated communication between the client and server should carry a digital signature (message integrity). 0x00000020Negotiate SealSpecifies that authenticated communication between the client and server should be encrypted (message confidentiality). 0x00000040Negotiate Datagram StyleIndicates that datagram authentication is being used. 0x00000080Negotiate Lan Manager KeyIndicates that the Lan Manager Session Key should be used for signing and sealing authenticated communications. 0x00000100Negotiate NetwareThis flag's usage has not been identified. 0x00000200Negotiate NTLMIndicates that NTLM authentication is being used. 0x00000400unknownThis flag's usage has not been identified. 0x00000800Negotiate AnonymousSent by the client in the Type 3 message to indicate that an anonymous context has been established. This also affects the response fields (as detailed in the "Anonymous Response" section). 0x00001000Negotiate Domain SuppliedSent by the client in the Type 1 message to indicate that the name of the domain in which the client workstation has membership is included in the message. This is used by the server to determine whether the client is eligible for local authentication. 0x00002000Negotiate Workstation SuppliedSent by the client in the Type 1 message to indicate that the client workstation's name is included in the message. This is used by the server to determine whether the client is eligible for local authentication. 0x00004000Negotiate Local CallSent by the server to indicate that the server and client are on the same machine. Implies that the client may use the established local credentials for authentication instead of calculating a response to the challenge. 0x00008000Negotiate Always SignIndicates that authenticated communication between the client and server should be signed with a "dummy" signature. 0x00010000Target Type DomainSent by the server in the Type 2 message to indicate that the target authentication realm is a domain. 0x00020000Target Type ServerSent by the server in the Type 2 message to indicate that the target authentication realm is a server. 0x00040000Target Type ShareSent by the server in the Type 2 message to indicate that the target authentication realm is a share. Presumably, this is for share-level authentication. Usage is unclear. 0x00080000Negotiate NTLM2 KeyIndicates that the NTLM2 signing and sealing scheme should be used for protecting authenticated communications. Note that this refers to a particular session security scheme, and is not related to the use of NTLMv2 authentication. This flag can, however, have an effect on the response calculations (as detailed in the "NTLM2 Session Response" section). 0x00100000Request Init ResponseThis flag's usage has not been identified. 0x00200000Request Accept ResponseThis flag's usage has not been identified. 0x00400000Request Non-NT Session KeyThis flag's usage has not been identified. 0x00800000Negotiate Target InfoSent by the server in the Type 2 message to indicate that it is including a Target Information block in the message. The Target Information block is used in the calculation of the NTLMv2 response. 0x01000000unknownThis flag's usage has not been identified. 0x02000000unknownThis flag's usage has not been identified. 0x04000000unknownThis flag's usage has not been identified. 0x08000000unknownThis flag's usage has not been identified. 0x10000000unknownThis flag's usage has not been identified. 0x20000000Negotiate 128Indicates that 128-bit encryption is supported. 0x40000000Negotiate Key ExchangeIndicates that the client will provide an encrypted master key in the "Session Key" field of the Type 3 message. 0x80000000Negotiate 56Indicates that 56-bit encryption is supported.
As an example, consider a message specifying:
Negotiate Unicode (0x00000001)
Request Target (0x00000004)
Negotiate NTLM (0x00000200)
Negotiate Always Sign (0x00008000)
Combining the above gives "0x00008205". This would be physically laid out as "0x05820000" (since it is represented in little-endian byte order).
The Type 1 Message
Let's jump in and take a look at the Type 1 message:
DescriptionContent0NTLMSSP SignatureNull-terminated ASCII "NTLMSSP" (0x4e544c4d53535000)8NTLM Message Typelong (0x01000000)12Flagslong(16)Supplied Domain (Optional)security buffer(24)Supplied Workstation (Optional)security buffer(32)OS Version Structure (Optional)8 bytes(32) (40)start of data block (if required)
The Type 1 message is sent from the client to the server to initiate NTLM authentication. Its primary purpose is to establish the "ground rules" for authentication by indicating supported options via the flags. Optionally, it can also provide the server with the client's workstation name and the domain in which the client workstation has membership; this information is used by the server to determine whether the client is eligible for local authentication.
Typically, the Type 1 message contains flags from the following set:
Negotiate Unicode (0x00000001)The client sets this flag to indicate that it supports Unicode strings. Negotiate OEM (0x00000002)This is set to indicate that the client supports OEM strings. Request Target (0x00000004)This requests that the server send the authentication target with the Type 2 reply. Negotiate NTLM (0x00000200)Indicates that NTLM authentication is supported. Negotiate Domain Supplied (0x00001000)When set, the client will send with the message the name of the domain in which the workstation has membership. Negotiate Workstation Supplied (0x00002000)Indicates that the client is sending its workstation name with the message. Negotiate Always Sign (0x00008000)Indicates that communication between the client and server after authentication should carry a "dummy" signature. Negotiate NTLM2 Key (0x00080000)Indicates that this client supports the NTLM2 signing and sealing scheme; if negotiated, this can also affect the response calculations. Negotiate 128 (0x20000000)Indicates that this client supports strong (128-bit) encryption. Negotiate 56 (0x80000000)Indicates that this client supports medium (56-bit) encryption.
The supplied domain is a security buffer containing the domain in which the client workstation has membership. This is always in OEM format, even if Unicode is supported by the client.
The supplied workstation is a security buffer containing the client workstation's name. This, too, is in OEM rather than Unicode.

The OS Version structure was introduced in recent Windows updates; it identifies the host's operating system build level, and is formatted as follows: DescriptionContent0Major Version Number1 byte1Minor Version Number1 byte2Build Numbershort4Unknown0x0000000f
The operating system build can be found by running "winver.exe"; it should give a string similar to:
```
    Version 5.1 (Build 2600.xpsp_sp2_gdr.050301-1519 : Service Pack 2)
```
This yields an OS Version structure of "0x0501280a0000000f": 0x05(major version 5)0x01(minor version 1; Windows XP)0x280a(build number 2600 in hexadecimal little-endian)0x0000000f(unknown/reserved)
Note that the OS Version structure and the supplied domain/workstation are optional fields. There are three versions of the Type 1 message that have been observed in the wild:
1. Version 1 -- The Supplied Domain and Workstation security buffers and OS Version structure are omitted completely. In this case the message ends after the flags field, and is a fixed-length 16-byte structure. This form is typically seen in older Win9x-based systems, and is roughly documented in the Open Group's ActiveX reference documentation (
Section 11.2.2).
Version 2 -- The Supplied Domain and Workstation buffers are present, but the OS Version structure is not. The data block begins immediately after the security buffer headers, at offset 32. This form is seen in most out-of-box shipping versions of Windows.
Version 3 -- Both the Supplied Domain/Workstation buffers are present, as well as the OS Version structure. The data block begins after the OS Version structure, at offset 40. This form was introduced in a relatively recent Service Pack, and is seen on currently-patched versions of Windows 2000, Windows XP, and Windows 2003.

The "most-minimal" well-formed Type 1 message, therefore, would be:

    4e544c4d535350000100000002020000

This is a "Version 1" Type 1 message containing only the NTLMSSP signature, the NTLM message type, and the minimal set of flags (Negotiate NTLM and Negotiate OEM). Local Authentication" section.

Type 1 Message Example

Consider the following hexadecimal Type 1 Message:

    4e544c4d53535000010000000732000006000600330000000b000b0028000000    050093080000000f574f524b53544154494f4e444f4d41494e

We break this up as follows:

00x4e544c4d53535000NTLMSSP Signature80x01000000Type 1 Indicator120x07320000Flags:

Negotiate Unicode (0x00000001)
Negotiate OEM (0x00000002)
Request Target (0x00000004)
Negotiate NTLM (0x00000200)
Negotiate Domain Supplied (0x00001000)
Negotiate Workstation Supplied (0x00002000)

160x0600060033000000Supplied Domain Security Buffer:

Length: 6 bytes (0x0600)
Allocated Space: 6 bytes (0x0600)
Offset: 51 bytes (0x33000000)

240x0b000b0028000000Supplied Workstation Security Buffer:

Length: 11 bytes (0x0b00)
Allocated Space: 11 bytes (0x0b00)
Offset: 40 bytes (0x28000000)

320x050093080000000fOS Version Structure:

Major Version: 5 (0x05)
Minor Version: 0 (0x00)
Build Number: 2195 (0x9308)
Unknown/Reserved (0x0000000f)

400x574f524b53544154494f4eSupplied Workstation Data ("WORKSTATION")510x444f4d41494eSupplied Domain Data ("DOMAIN")

Analyzing this information, we can see:

This is an NTLM Type 1 message (from the NTLMSSP Signature and Type 1 Indicator).
This client can support either Unicode or OEM strings (the Negotiate Unicode and Negotiate OEM flags are both set).
This client supports NTLM authentication (Negotiate NTLM).
The client is requesting that the server send information regarding the authentication target (Request Target is set).
The client is running Windows 2000 (5.0), build 2195 (the production build number for Windows 2000 systems).
This client is sending its domain, which is "DOMAIN" (the Negotiate Domain Supplied flag is set, and the domain name is present in the Supplied Domain Security Buffer).
The client is sending its workstation name, which is "WORKSTATION" (the Negotiate Workstation Supplied flag is set, and the workstation name is present in the Supplied Workstation Security Buffer).

Note that the supplied workstation and domain are in OEM format. Additionally, the order in which the security buffer data blocks are laid out is unimportant; in the example, the workstation data is placed before the domain data.

After creating the Type 1 message, the client sends it to the server. The server analyzes the message, much as we have just done, and creates a reply. This brings us to our next topic, the Type 2 message.

The Type 2 Message

DescriptionContent0NTLMSSP SignatureNull-terminated ASCII "NTLMSSP" (0x4e544c4d53535000)8NTLM Message Typelong (0x02000000)12Target Namesecurity buffer20Flagslong24Challenge8 bytes(32)Context (optional)8 bytes (two consecutive longs)(40)Target Information (optional)security buffer(48)OS Version Structure (Optional)8 bytes32 (48) (56)start of data block

The Type 2 message is sent by the server to the client in response to the client's Type 1 message. It serves to complete the negotiation of options with the client, and also provides a challenge to the client. It may optionally contain information about the authentication target.

Typical Type 2 message flags include:

Negotiate Unicode (0x00000001)The server sets this flag to indicate that it will be using Unicode strings. This should only be set if the client indicates (in the Type 1 message) that it supports Unicode. Either this flag or Negotiate OEM should be set, but not both. Negotiate OEM (0x00000002)This flag is set to indicate that the server will be using OEM strings. This should only be set if the client indicates (in the Type 1 message) that it will support OEM strings. Either this flag or Negotiate Unicode should be set, but not both. Request Target (0x00000004)This flag is often set in the Type 2 message; while it has a well-defined meaning within the Type 1 message, its semantics here are unclear. Negotiate NTLM (0x00000200)Indicates that NTLM authentication is supported. Negotiate Local Call (0x00004000)The server sets this flag to inform the client that the server and client are on the same machine. The server provides a local security context handle with the message. Negotiate Always Sign (0x00008000)Indicates that communication between the client and server after authentication should carry a "dummy" signature. Target Type Domain (0x00010000)The server sets this flag to indicate that the authentication target is being sent with the message and represents a domain. Target Type Server (0x00020000)The server sets this flag to indicate that the authentication target is being sent with the message and represents a server. Target Type Share (0x00040000)The server apparently sets this flag to indicate that the authentication target is being sent with the message and represents a network share. This has not been confirmed. Negotiate NTLM2 Key (0x00080000)Indicates that this server supports the NTLM2 signing and sealing scheme; if negotiated, this can also affect the client's response calculations. Negotiate Target Info (0x00800000)The server sets this flag to indicate that a Target Information block is being sent with the message. Negotiate 128 (0x20000000)Indicates that this server supports strong (128-bit) encryption. Negotiate 56 (0x80000000)Indicates that this server supports medium (56-bit) encryption.

The target name is a security buffer containing the name of the authentication target. This is typically sent in response to a client requesting the target (via the Request Target flag in the Type 1 message). This can contain a domain, server, or (apparently) a network share. The target type is indicated via the Target Type Domain, Target Type Server, and Target Type Share flags. The target name can be either Unicode or OEM, as indicated by the presence of the appropriate flag in the Type 2 message.

The challenge is an 8-byte block of random data. The client will use this to formulate a response.

The context field is typically populated when Negotiate Local Call is set. It contains an SSPI context handle, which allows the client to "short-circuit" authentication and effectively circumvent responding to the challenge. Physically, the context is two long values. This is covered in greater detail later, in the "

The target information is a security buffer containing a Target Information block, which is used in calculating the NTLMv2 response (discussed later). This is composed of a sequence of subblocks, each consisting of:

FieldContentDescriptionTypeshortIndicates the type of data in this subblock: 1 (0x0100):Server name2 (0x0200):Domain name3 (0x0300):Fully-qualified DNS host name (i.e., server.domain.com) 4 (0x0400):DNS domain name (i.e., domain.com)LengthshortLength in bytes of this subblock's content fieldContentUnicode stringContent as indicated by the type field. Always sent in Unicode, even when OEM is indicated by the message flags.

The sequence is terminated by a terminator subblock; this is a subblock of type "0", of zero length. Subblocks of type "5" have also been encountered, apparently containing the "parent" DNS domain for servers in subdomains; it may be that there are other as-yet-unidentified subblock types as well.

The OS Version structure was described previously.

As with the Type 1 message, there are a few versions of the Type 2 that have been observed:

Version 1 -- The Context, Target Information, and OS Version structure are all omitted. The data block (containing only the contents of the Target Name security buffer) begins at offset 32. This form is seen in older Win9x-based systems, and is roughly documented in the Open Group's ActiveX reference documentation (Section 11.2.3).
Version 2 -- The Context and Target Information fields are present, but the OS Version structure is not. The data block begins after the Target Information header, at offset 48. This form is seen in most out-of-box shipping versions of Windows.
Version 3 -- The Context, Target Information, and OS Version structure are all present. The data block begins after the OS Version structure, at offset 56. Again, the buffers may be empty (yielding a zero-length data block). This form was introduced in a relatively recent Service Pack, and is seen on currently-patched versions of Windows 2000, Windows XP, and Windows 2003.

A minimal Type 2 message would look something like this:

    4e544c4d53535000020000000000000000000000020200000123456789abcdef

This message contains the NTLMSSP signature, the NTLM message type, an empty target name, minimal flags (Negotiate NTLM and Negotiate OEM), and the challenge. datagram-style authentication, however.

Type 2 Message Example

Let's look at the following hexadecimal Type 2 Message:

    4e544c4d53535000020000000c000c003000000001028100    0123456789abcdef0000000000000000620062003c000000    44004f004d00410049004e0002000c0044004f004d004100    49004e0001000c0053004500520056004500520004001400    64006f006d00610069006e002e0063006f006d0003002200    7300650072007600650072002e0064006f006d0061006900    6e002e0063006f006d0000000000

Breaking this into its constituent fields gives:

00x4e544c4d53535000NTLMSSP Signature80x02000000Type 2 Indicator120x0c000c0030000000Target Name Security Buffer:

Length: 12 bytes (0x0c00)
Allocated Space: 12 bytes (0x0c00)
Offset: 48 bytes (0x30000000)

200x01028100Flags:

Negotiate Unicode (0x00000001)
Negotiate NTLM (0x00000200)
Target Type Domain (0x00010000)
Negotiate Target Info (0x00800000)

240x0123456789abcdefChallenge320x0000000000000000Context400x620062003c000000Target Information Security Buffer:

Length: 98 bytes (0x6200)
Allocated Space: 98 bytes (0x6200)
Offset: 60 bytes (0x3c000000)

0x44004f004d004100  49004e00

Target Name Data ("DOMAIN")60

0x02000c0044004f00  4d00410049004e00  01000c0053004500  5200560045005200  0400140064006f00  6d00610069006e00  2e0063006f006d00  0300220073006500  7200760065007200  2e0064006f006d00  610069006e002e00  63006f006d000000  0000

Target Information Data:

0x02000c0044004f00  4d00410049004e00

Domain name subblock:

Type: 2 (Domain name, 0x0200)
Length: 12 bytes (0x0c00)
Data: "DOMAIN"

0x01000c0053004500  5200560045005200

Server name subblock:

Type: 1 (Server name, 0x0100)
Length: 12 bytes (0x0c00)
Data: "SERVER"

0x0400140064006f00  6d00610069006e00  2e0063006f006d00

DNS domain name subblock:

Type: 4 (DNS domain name, 0x0400)
Length: 20 bytes (0x1400)
Data: "domain.com"

0x0300220073006500  7200760065007200  2e0064006f006d00  610069006e002e00  63006f006d00

DNS server name subblock:

Type: 3 (DNS server name, 0x0300)
Length: 34 bytes (0x2200)
Data: "server.domain.com"

0x00000000Terminator subblock:

Type: 0 (terminator, 0x0000)
Length: 0 bytes (0x0000)

An analysis of this message shows:

This is an NTLM Type 2 message (from the NTLMSSP Signature and Type 2 Indicator).
The server has indicated that strings will be encoded using Unicode (the Negotiate Unicode flag is set).
The server supports NTLM authentication (Negotiate NTLM).
The Target Name provided by the server is populated and represents a domain (the Target Type Domain flag is set and the domain name is present in the Target Name Security Buffer).
The server is providing a Target Information structure (Negotiate Target Info is set). This structure is present in the Target Information Security Buffer (domain name "DOMAIN", server name "SERVER", DNS domain name "domain.com", and DNS server name "server.domain.com").
The challenge generated by the server is "0x0123456789abcdef".
An empty context has been sent.

Note that the target name is in Unicode format (as specified by the Negotiate Unicode flag).

After the server creates the Type 2 message, it is sent to the client. The response to the server's challenge is provided in the client's Type 3 message.

The Type 3 Message

DescriptionContent0NTLMSSP SignatureNull-terminated ASCII "NTLMSSP" (0x4e544c4d53535000)8NTLM Message Typelong (0x03000000)12LM/LMv2 Responsesecurity buffer20NTLM/NTLMv2 Responsesecurity buffer28Target Namesecurity buffer36User Namesecurity buffer44Workstation Namesecurity buffer(52)Session Key (optional)security buffer(60)Flags (optional)long(64)OS Version Structure (Optional)8 bytes52 (64) (72)start of data block

The Type 3 message is the final step in authentication. This message contains the client's responses to the Type 2 challenge, which demonstrate that the client has knowledge of the account password without sending the password directly. The Type 3 message also indicates the authentication target (domain or server name) and username of the authenticating account, as well as the client workstation name.

Note that the flags in the Type 3 message are optional; older clients include neither the session key nor the flags in the message. It has been determined experimentally that the Type 3 flags (when included) do not carry any additional semantics in connection-oriented authentication; they do not appear to have any discernable effect on either authentication or the establishment of session security. Clients sending flags typically mirror the established Type 2 settings fairly closely. It is possible that the flags are sent as a "reminder" of established options, to allow the server to avoid caching the negotiated settings. The Type 3 flags are relevant during

The LM/LMv2 and NTLM/NTLMv2 responses are security buffers containing replies created from the user's password in response to the Type 2 challenge; the process for generating these responses is outlined in the next section.

The target name is a security buffer containing the authentication realm in which the authenticating account has membership (a domain name for domain accounts, or server name for local machine accounts). This is either Unicode or OEM, depending on the negotiated encoding.

The user name is a security buffer containing the authenticating account name. This is either Unicode or OEM, depending on the negotiated encoding.

The workstation name is a security buffer containing the client workstation's name. This is either Unicode or OEM, depending on the negotiated encoding.

The session key value is used by the session security mechanism during key exchange; this is discussed in more detail in the Session Security section.

When "Negotiate Local Call" has been established in the Type 2 message, the security buffers in the Type 3 message are typically all empty (zero length). The client "adopts" the SSPI context sent in the Type 2 message, effectively circumventing the need to calculate an appropriate response.

The OS Version structure is the same format described previously.

Again, there are a few variations of the Type 3 message:

Version 1 -- The Session Key, flags, and OS Version structure are omitted. The data block in this case starts after the Workstation Name security buffer header, at offset 52. This form is seen in older Win9x-based systems.
Version 2 -- The Session Key and flags are included, but the OS Version structure is not. In this case, the data block begins after the flags field, at offset 64. This form is seen in most out-of-box shipping versions of Windows, and is roughly documented in the Open Group's ActiveX reference documentation (Section 11.2.4).
Version 3 -- The Session Key, flags, and OS Version structure are all present. The data block begins after the OS Version structure, at offset 72. This form was introduced in a relatively recent Service Pack, and is seen on currently-patched versions of Windows 2000, Windows XP, and Windows 2003.

Name Variations

In addition to the variations in message layout, user and target names can be presented in a few different formats within the Type 3 message. In the typical scenario, the User Name field is populated with the Windows account name, and the Target Name is populated with the NT domain name. However, the username and/or domain can also be presented in the Kerberos-style "user@domain.com" format in various combinations. It has been observed that several variations are supported, with some possible implications/caveats: FormatType 3 Field ContentNotesDOMAIN/userUser Name = "user"
Target Name = "DOMAIN" This is the "normal" format; the User Name field contains the Windows user name, and the Target Name contains the NT-style NetBIOS domain or server name. domain.com/userUser Name = "user"
Target Name = "domain.com" Here, the Target Name field in the Type 3 message is populated with the DNS domain/realm name (or fully-qualified DNS host name in the case of local machine accounts). user@DOMAINUser Name = "user@DOMAIN"
Target Name is empty In this case, the Target Name field is empty (zero-length), and the User Name field uses the Kerberos-style "user@realm" format; however, the NetBIOS domain name is used instead of the DNS domain. It has been observed that this format is not supported for local machine accounts; additionally, this form does not appear to be supported under NTLMv2/LMv2 authentication. user@domain.comUser Name = "user@domain.com"
Target Name is empty Here, the Target Name field in the Type 3 message is empty; the User Name field contains the Kerberos-style "user@realm" format, with the DNS domain. This form does not appear to be supported for local machine accounts.

Implementing CIFS, especially the section on authentication.

Responding to the Challenge

The client creates one or more responses to the Type 2 challenge, and sends these to the server in the Type 3 message. There are six types of responses:

LM (LAN Manager) Response - Sent by most older clients, this is the "original" response type.
NTLM Response - This is sent by NT-based clients, including Windows 2000 and XP.
NTLMv2 Response - A newer response type, introduced in Windows NT Service Pack 4. This replaces the NTLM response on systems that have NTLM version 2 enabled.
LMv2 Response - The replacement for the LM response on NTLM version 2 systems.
NTLM2 Session Response - Used when NTLM2 session security is negotiated without NTLMv2 authentication, this scheme alters the semantics of both the LM and NTLM responses.
Anonymous Response - This is used when an anonymous context is being established; actual credentials are not presented, and no true authentication takes place. "Stub" fields are presented in the Type 3 message.

For more information on these schemes, it is highly recommended that you read Christopher Hertel's

The responses serve as an indirect proof of knowledge of the password. The password is used by the client to derive the LM and/or NTLM hash (discussed in the next section); these values are in turn used to calculate an appropriate response to the challenge. The domain controller (or server for local machine accounts) stores the LM and NTLM hashes for the password; when the response is received from the client, these stored values are used to calculate the appropriate response values which are compared to those sent by the client. A match yields a successful authentication of the user.

Note that unlike Unix password hashes, the LM and NTLM hash are password-equivalents in the context of the response calculations; they must be protected, as they can be used to authenticate users across the network even without knowledge of the actual password itself. Appendix D for a sample implementation in Java):

The LM Response

The LM response is sent by most clients. This scheme is older than the NTLM response, and less secure. While newer clients support the NTLM response, they typically send both responses for compatibility with legacy servers; hence, the security flaws present in the LM response are still exhibited in many clients supporting the NTLM response.

The LM response is calculated as follows (see

The user's password (as an OEM string) is converted to uppercase.
This password is null-padded to 14 bytes.
This "fixed" password is split into two 7-byte halves.
These values are used to create two DES keys (one from each 7-byte half).
Each of these keys is used to DES-encrypt the constant ASCII string "KGS!@#$%" (resulting in two 8-byte ciphertext values).
These two ciphertext values are concatenated to form a 16-byte value - the LM hash.
The 16-byte LM hash is null-padded to 21 bytes.
This value is split into three 7-byte thirds.
These values are used to create three DES keys (one from each 7-byte third).
Each of these keys is used to DES-encrypt the challenge from the Type 2 message (resulting in three 8-byte ciphertext values).
These three ciphertext values are concatenated to form a 24-byte value. This is the LM response.

In the event that the user's password is longer than 15 characters, the host or domain controller will not store the LM hash for the user; the LM response cannot be used to authenticate the user in this case. A response is still generated and placed in the LM Response field, using a 16-byte null value (0x00000000000000000000000000000000) as the LM hash in the calculation. This value is ignored by the target.

The response calculation process is best illustrated with a detailed example. Consider a user with the password "SecREt01", responding to the Type 2 challenge "0x0123456789abcdef".

The password (as an OEM string) is converted to uppercase, giving "SECRET01" (or "0x5345435245543031" in hexadecimal).
This password is null-padded to 14 bytes, giving "0x5345435245543031000000000000".
This value is split into two 7-byte halves, "0x53454352455430" and "0x31000000000000".
These two values are used to create two DES keys. A DES key is 8 bytes long; each byte contains seven bits of key material and one odd-parity bit (the parity bit may or may not be checked, depending on the underlying DES implementation). Our first 7-byte value, "0x53454352455430", would be represented in binary as:
01010011 01000101 01000011 01010010 01000101 01010100 00110000
A non-parity-adjusted DES key for this value would be:
01010010 10100010 01010000 01101010 00100100 00101010 01010000 01100000
(the parity bits are shown in red above). This is "0x52a2506a242a5060" in hexadecimal. Applying odd-parity to ensure that the total number of set bits in each octet is odd gives:
01010010 10100010 01010001 01101011 00100101 00101010 01010001 01100001
This is the first DES key ("0x52a2516b252a5161" in hex). We then apply the same process to our second 7-byte value, "0x31000000000000", represented in binary as:
00110001 00000000 00000000 00000000 00000000 00000000 00000000
Creating a non-parity-adjusted DES key gives:
00110000 10000000 00000000 00000000 00000000 00000000 00000000 00000000
("0x3080000000000000" in hexadecimal). Adjusting the parity bits gives:
00110001 10000000 00000001 00000001 00000001 00000001 00000001 00000001
This is our second DES key, "0x3180010101010101" in hexadecimal. Note that if our particular DES implementation does not enforce parity (many do not), the parity-adjustment steps can be skipped; the non-parity-adjusted values would then be used as the DES keys. In any case, the parity bits will not affect the encryption process.
Each of our keys is used to DES-encrypt the constant ASCII string "KGS!@#$%" ("0x4b47532140232425" in hex). This gives us "0xff3750bcc2b22412" (using the first key) and "0xc2265b23734e0dac" (using the second).
These ciphertext values are concatenated to form our 16-byte LM hash - "0xff3750bcc2b22412c2265b23734e0dac".
This is null-padded to 21 bytes, giving "0xff3750bcc2b22412c2265b23734e0dac0000000000".
This value is split into three 7-byte thirds, "0xff3750bcc2b224", "0x12c2265b23734e" and "0x0dac0000000000".
These three values are used to create three DES keys. Using the process outlined previously, our first value:
11111111 00110111 01010000 10111100 11000010 10110010 00100100
Gives us the parity-adjusted DES key:
11111110 10011011 11010101 00010110 11001101 00010101 11001000 01001001
("0xfe9bd516cd15c849" in hexadecimal). The second value:
00010010 11000010 00100110 01011011 00100011 01110011 01001110
Results in the key:
00010011 01100001 10001001 11001011 10110011 00011010 11001101 10011101
("0x136189cbb31acd9d"). Finally, the third value:
00001101 10101100 00000000 00000000 00000000 00000000 00000000
Gives us:
00001101 11010110 00000001 00000001 00000001 00000001 00000001 00000001
This is the third DES key ("0x0dd6010101010101").
Each of the three keys is used to DES-encrypt the challenge from the Type 2 message (in our example, "0x0123456789abcdef"). This gives the results "0xc337cd5cbd44fc97" (using the first key), "0x82a667af6d427c6d" (using the second) and "0xe67c20c2d3e77c56" (using the third).
These three ciphertext values are concatenated to form the 24-byte LM response:
0xc337cd5cbd44fc9782a667af6d427c6de67c20c2d3e77c56

There are several weaknesses in this algorithm which make it susceptible to attack. While these are covered in detail in the Hertel text, the most prominent problems are:

Passwords are converted to upper case before calculating the response. This significantly reduces the set of possible passwords that must be tested in a brute-force attack.
If the password is seven or fewer characters, the second value from step 3 above will be 7 null bytes. This effectively compromises half of the LM hash (as it will always be the ciphertext of "KGS!@#$%" encrypted with the DES key "0x0101010101010101" - the constant "0xaad3b435b51404ee"). This in turn compromises the three DES keys used to produce the response; the entire third key and all but one byte of the second will be known constant values.

The NTLM Response

The NTLM response is sent by newer clients. This scheme addresses some of the flaws in the LM response; however, it is still considered fairly weak. Additionally, the NTLM response is nearly always sent in conjunction with the LM response. The weaknesses in that algorithm can be exploited to obtain the case-insensitive password, and trial-and-error used to find the case-sensitive password employed by the NTLM response.

The NTLM response is calculated as follows (see

Appendix D for a sample Java implementation):

The MD4 message-digest algorithm (described in RFC 1320) is applied to the Unicode mixed-case password. This results in a 16-byte value - the NTLM hash.
The 16-byte NTLM hash is null-padded to 21 bytes.
This value is split into three 7-byte thirds.
These values are used to create three DES keys (one from each 7-byte third).
Each of these keys is used to DES-encrypt the challenge from the Type 2 message (resulting in three 8-byte ciphertext values).
These three ciphertext values are concatenated to form a 24-byte value. This is the NTLM response.

Note that only the calculation of the hash value differs from the LM scheme; the response calculation is the same. To illustrate this process, we will apply it to our previous example (a user with the password "SecREt01", responding to the Type 2 challenge "0x0123456789abcdef").

The Unicode mixed-case password is "0x53006500630052004500740030003100" in hexadecimal; the MD4 hash of this value is calculated, giving "0xcd06ca7c7e10c99b1d33b7485a2ed808". This is the NTLM hash.
This is null-padded to 21 bytes, giving "0xcd06ca7c7e10c99b1d33b7485a2ed8080000000000".
This value is split into three 7-byte thirds, "0xcd06ca7c7e10c9", "0x9b1d33b7485a2e" and "0xd8080000000000".
These three values are used to create three DES keys. Our first value:
11001101 00000110 11001010 01111100 01111110 00010000 11001001
Results in the parity-adjusted key:
11001101 10000011 10110011 01001111 11000111 11110001 01000011 10010010
("0xcd83b34fc7f14392" in hexadecimal). The second value:
10011011 00011101 00110011 10110111 01001000 01011010 00101110
Gives the key:
10011011 10001111 01001100 01110110 01110101 01000011 01101000 01011101
("0x9b8f4c767543685d"). Our third value:
11011000 00001000 00000000 00000000 00000000 00000000 00000000
Yields our third key:
11011001 00000100 00000001 00000001 00000001 00000001 00000001 00000001
("0xd904010101010101" in hexadecimal).
Each of the three keys is used to DES-encrypt the challenge from the Type 2 message ("0x0123456789abcdef"). This yields the results "0x25a98c1c31e81847" (using our first key), "0x466b29b2df4680f3" (using the second) and "0x9958fb8c213a9cc6" (using the third key).
These three ciphertext values are concatenated to form the 24-byte NTLM response:
0x25a98c1c31e81847466b29b2df4680f39958fb8c213a9cc6

The NTLMv2 Response

NTLM version 2 ("NTLMv2") was concocted to address the security issues present in NTLM. When NTLMv2 is enabled, the NTLM response is replaced with the NTLMv2 response, and the LM response is replaced with the LMv2 response (which we will discuss next).

The NTLMv2 response is calculated as follows (see

Appendix D for a sample implementation in Java):

The NTLM password hash is obtained (as discussed previously, this is the MD4 digest of the Unicode mixed-case password).
The Unicode uppercase username is concatenated with the Unicode authentication target (the domain or server name specified in the Target Name field of the Type 3 message). Note that this calculation always uses the Unicode representation, even if OEM encoding has been negotiated; also note that the username is converted to uppercase, while the authentication target is case-sensitive and must match the case presented in the Target Name field.
The HMAC-MD5 message authentication code algorithm (described in RFC 2104) is applied to this value using the 16-byte NTLM hash as the key. This results in a 16-byte value - the NTLMv2 hash.
A block of data known as the "blob" is constructed. The Hertel text discusses the format of this structure in greater detail; briefly: DescriptionContent0Blob Signature0x010100004Reservedlong (0x00000000)8TimestampLittle-endian, 64-bit signed value representing the number of tenths of a microsecond since January 1, 1601. 16Client Nonce8 bytes24Unknown4 bytes28Target InformationTarget Information block (from the Type 2 message).(variable)Unknown4 bytes
The challenge from the Type 2 message is concatenated with the blob. The HMAC-MD5 message authentication code algorithm is applied to this value using the 16-byte NTLMv2 hash (calculated in step 2) as the key. This results in a 16-byte output value.
This value is concatenated with the blob to form the NTLMv2 response.

Let's look at an example. Since we need a bit more information to calculate the NTLMv2 response, we will use the following values from the examples presented previously:

Target:DOMAINUsername:userPassword:SecREt01Challenge:0x0123456789abcdefTarget Information:

0x02000c0044004f00  4d00410049004e00  01000c0053004500  5200560045005200  0400140064006f00  6d00610069006e00  2e0063006f006d00  0300220073006500  7200760065007200  2e0064006f006d00  610069006e002e00  63006f006d000000  0000

The Unicode mixed-case password is "0x53006500630052004500740030003100" in hexadecimal; the MD4 hash of this value is calculated, giving "0xcd06ca7c7e10c99b1d33b7485a2ed808". This is the NTLM hash.
The Unicode uppercase username is concatenated with the Unicode authentication target, giving "USERDOMAIN" (or "0x550053004500520044004f004d00410049004e00" in hexadecimal). HMAC-MD5 is applied to this value using the 16-byte NTLM hash from the previous step as the key, which yields "0x04b8e0ba74289cc540826bab1dee63ae". This is the NTLMv2 hash.
Next, the blob is constructed. The timestamp is the most tedious part of this; looking at the clock on my desk, it's about 6:00 AM EDT on June 17th, 2003. In Unix time, that would be 1055844000 seconds after the Epoch. Adding 11644473600 will give us seconds after January 1, 1601 (12700317600). Multiplying by 10⁷ (10000000) will give us tenths of a microsecond (127003176000000000). As a little-endian 64-bit value, this is "0x0090d336b734c301" (in hexadecimal).
We also need to generate an 8-byte random "client nonce"; we will use the not-so-random "0xffffff0011223344". Constructing the rest of the blob is easy; we just concatenate:
0x01010000(the blob signature)0x00000000(reserved value)0x0090d336b734c301(our timestamp)0xffffff0011223344(a random client nonce)0x00000000(unknown, but zero will work)
```
0x02000c0044004f00  4d00410049004e00  01000c0053004500  5200560045005200  0400140064006f00  6d00610069006e00  2e0063006f006d00  0300220073006500  7200760065007200  2e0064006f006d00  610069006e002e00  63006f006d000000  0000
```
(our target information block)0x00000000(unknown, but zero will work)

We then concatenate the Type 2 challenge with our blob:

0x0123456789abcdef0101000000000000  0090d336b734c301ffffff0011223344  0000000002000c0044004f004d004100  49004e0001000c005300450052005600  450052000400140064006f006d006100  69006e002e0063006f006d0003002200  7300650072007600650072002e006400  6f006d00610069006e002e0063006f00  6d000000000000000000

Applying HMAC-MD5 to this value using the NTLMv2 hash from step 2 as the key gives us the 16-byte value "0xcbabbca713eb795d04c97abc01ee4983".

This value is concatenated with the blob to obtain the NTLMv2 response:

0xcbabbca713eb795d04c97abc01ee4983  01010000000000000090d336b734c301  ffffff00112233440000000002000c00  44004f004d00410049004e0001000c00  53004500520056004500520004001400  64006f006d00610069006e002e006300  6f006d00030022007300650072007600  650072002e0064006f006d0061006900  6e002e0063006f006d00000000000000  0000

The LMv2 Response

The LMv2 response is used to provide pass-through authentication compatibility with older servers. It is quite possible that the server with which the client is communicating will not actually perform the authentication; rather, it will pass the responses through to a domain controller for verification. Older servers pass only the LM response, and expect it to be exactly 24 bytes. The LMv2 response was designed to allow such servers to operate properly; it is effectively a "miniature" NTLMv2 response, obtained as follows (see

Appendix D for a sample Java implementation):

The NTLM password hash is calculated (the MD4 digest of the Unicode mixed-case password).
The Unicode uppercase username is concatenated with the Unicode authentication target (domain or server name) presented in the Target Name field of the Type 3 message. The HMAC-MD5 message authentication code algorithm is applied to this value using the 16-byte NTLM hash as the key. This results in a 16-byte value - the NTLMv2 hash.
A random 8-byte client nonce is created (this is the same client nonce used in the NTLMv2 blob).
The challenge from the Type 2 message is concatenated with the client nonce. The HMAC-MD5 message authentication code algorithm is applied to this value using the 16-byte NTLMv2 hash (calculated in step 2) as the key. This results in a 16-byte output value.
This value is concatenated with the 8-byte client nonce to form the 24-byte LMv2 response.

We will illustrate this process with a brief example using our tried-and-true sample values:

Target:DOMAINUsername:userPassword:SecREt01Challenge:0x0123456789abcdef

The Unicode mixed-case password is "0x53006500630052004500740030003100" in hexadecimal; the MD4 hash of this value is calculated, giving "0xcd06ca7c7e10c99b1d33b7485a2ed808". This is the NTLM hash.
The Unicode uppercase username is concatenated with the Unicode authentication target, giving "USERDOMAIN" (or "0x550053004500520044004f004d00410049004e00" in hexadecimal). HMAC-MD5 is applied to this value using the 16-byte NTLM hash from the previous step as the key, which yields "0x04b8e0ba74289cc540826bab1dee63ae". This is the NTLMv2 hash.
A random 8-byte client nonce is created. From our NTLMv2 example, we will use "0xffffff0011223344".
We then concatenate the Type 2 challenge with our client nonce:
0x0123456789abcdefffffff0011223344
Applying HMAC-MD5 to this value using the NTLMv2 hash from step 2 as the key gives us the 16-byte value "0xd6e6152ea25d03b7c6ba6629c2d6aaf0".
This value is concatenated with the client nonce to obtain the 24-byte LMv2 response:
0xd6e6152ea25d03b7c6ba6629c2d6aaf0ffffff0011223344

The NTLM2 Session Response

The NTLM2 session response can be employed in conjunction with NTLM2 session security (it is made available with the "Negotiate NTLM2 Key" flag). This is used to provide enhanced protection against precomputed dictionary attacks (particularly Rainbow Table-based attacks) in environments which do not support full NTLMv2 authentication.

The NTLM2 session response replaces both the LM and NTLM response fields as follows (see

Appendix D for a sample implementation in Java):

A random 8-byte client nonce is created.
The client nonce is null-padded to 24 bytes. This value is placed in the LM response field of the Type 3 message.
The challenge from the Type 2 message is concatenated with the 8-byte client nonce to form a session nonce.
The MD5 message-digest algorithm (described in RFC 1321) is applied to the session nonce, resulting in a 16-byte value.
This value is truncated to 8 bytes to form the NTLM2 session hash.
The NTLM password hash is obtained (as discussed, this is the MD4 digest of the Unicode mixed-case password).
The 16-byte NTLM hash is null-padded to 21 bytes.
This value is split into three 7-byte thirds.
These values are used to create three DES keys (one from each 7-byte third).
Each of these keys is used to DES-encrypt the NTLM2 session hash (resulting in three 8-byte ciphertext values).
These three ciphertext values are concatenated to form a 24-byte value. This is the NTLM2 session response, which is placed in the NTLM response field of the Type 3 message.

To demonstrate this with our previous example values (a user with the password "SecREt01", responding to the Type 2 challenge "0x0123456789abcdef"):

A random 8-byte client nonce is created; we will use "0xffffff0011223344", as in the previous examples.
The challenge is null-padded to 24 bytes:
0xffffff001122334400000000000000000000000000000000
This value is placed in the LM response field of the Type 3 message.
The challenge from the Type 2 message is concatenated with the client nonce, forming a session nonce ("0x0123456789abcdefffffff0011223344").
Applying the MD5 digest to this nonce yields the 16-byte value "0xbeac9a1bc5a9867c15192b3105d5beb1".
This is truncated to 8 bytes to obtain the NTLM2 session hash ("0xbeac9a1bc5a9867c").
The Unicode mixed-case password is "0x53006500630052004500740030003100"; applying the MD4 digest to this value gives us the NTLM hash ("0xcd06ca7c7e10c99b1d33b7485a2ed808").
This is null-padded to 21 bytes, giving "0xcd06ca7c7e10c99b1d33b7485a2ed8080000000000".
This value is split into three 7-byte thirds, "0xcd06ca7c7e10c9", "0x9b1d33b7485a2e" and "0xd8080000000000".
These values are used to create three DES keys (as calculated in our previous NTLM response example, "0xcd83b34fc7f14392", "0x9b8f4c767543685d", and "0xd904010101010101").
Each of these three keys is used to DES-encrypt the NTLM2 session hash ("0xbeac9a1bc5a9867c"). This yields the results "0x10d550832d12b2cc" (using our first key), "0xb79d5ad1f4eed3df" (using the second), and "0x82aca4c3681dd455" (using the third key).
These three ciphertext values are concatenated to form the 24-byte NTLM2 session response:
0x10d550832d12b2ccb79d5ad1f4eed3df82aca4c3681dd455
which is placed in the NTLM response field of the Type 3 message.

The Anonymous Response

The Anonymous Response is seen when the client is establishing an anonymous context, rather than a true user-based context. This is typically seen when a "placeholder" is needed for operations that do not require an authenticated user. Anonymous connections are not the same as the Windows "Guest" user (the latter is an actual user account, while anonymous connections are associated with no account at all).

In an anonymous Type 3 message, the client indicates the "Negotiate Anonymous" flag; the NTLM response field is empty (zero-length); and the LM response field contains a single null byte ("0x00").

Type 3 Message Example

Now that we're familiar with the Type 3 responses, we are ready to examine a Type 3 Message:

    4e544c4d5353500003000000180018006a00000018001800    820000000c000c0040000000080008004c00000016001600    54000000000000009a0000000102000044004f004d004100    49004e00750073006500720057004f0052004b0053005400    4100540049004f004e00c337cd5cbd44fc9782a667af6d42    7c6de67c20c2d3e77c5625a98c1c31e81847466b29b2df46    80f39958fb8c213a9cc6

This message is decomposed as:

00x4e544c4d53535000NTLMSSP Signature80x03000000Type 3 Indicator120x180018006a000000LM Response Security Buffer:

Length: 24 bytes (0x1800)
Allocated Space: 24 bytes (0x1800)
Offset: 106 bytes (0x6a000000)

200x1800180082000000NTLM Response Security Buffer:

Length: 24 bytes (0x1800)
Allocated Space: 24 bytes (0x1800)
Offset: 130 bytes (0x82000000)

280x0c000c0040000000Target Name Security Buffer:

Length: 12 bytes (0x0c00)
Allocated Space: 12 bytes (0x0c00)
Offset: 64 bytes (0x40000000)

360x080008004c000000User Name Security Buffer:

Length: 8 bytes (0x0800)
Allocated Space: 8 bytes (0x0800)
Offset: 76 bytes (0x4c000000)

440x1600160054000000Workstation Name Security Buffer:

Length: 22 bytes (0x1600)
Allocated Space: 22 bytes (0x1600)
Offset: 84 bytes (0x54000000)

520x000000009a000000Session Key Security Buffer:

Length: 0 bytes (0x0000)
Allocated Space: 0 bytes (0x0000)
Offset: 154 bytes (0x9a000000)

600x01020000Flags:

Negotiate Unicode (0x00000001)
Negotiate NTLM (0x00000200)

0x44004f004d004100  49004e00

Target Name Data ("DOMAIN")760x7500730065007200User Name Data ("user")84

0x57004f0052004b00  5300540041005400  49004f004e00

Workstation Name Data ("WORKSTATION")106

0xc337cd5cbd44fc97  82a667af6d427c6d  e67c20c2d3e77c56

LM Response Data130

0x25a98c1c31e81847  466b29b2df4680f3  9958fb8c213a9cc6

NTLM Response Data

Analysis of this reveals:

This is an NTLM Type 3 message (from the NTLMSSP Signature and Type 3 Indicator).
The client has indicated that strings are encoded using Unicode (the Negotiate Unicode flag is set).
The client supports NTLM authentication (Negotiate NTLM).
The client's domain is "DOMAIN".
The client's username is "user".
The client's workstation is "WORKSTATION".
The client's LM response is "0xc337cd5cbd44fc9782a667af6d427c6de67c20c2d3e77c56".
The client's NTLM response is "0x25a98c1c31e81847466b29b2df4680f39958fb8c213a9cc6".
An empty session key has been sent.

Upon receipt of the Type 3 message, the server calculates the LM and NTLM responses and compares them to the values provided by the client; if they match, the user is successfully authenticated.

NTLM Version 2

NTLM version 2 consists of three new response algorithms (NTLMv2, LMv2, and the NTLM2 session response, discussed previously) and a new signing and sealing scheme (NTLM2 session security). NTLM2 session security is negotiated via the "Negotiate NTLM2 Key" flag; NTLMv2 authentication, however, is enabled through a modification to the registry. Further, the registry setting on the client and domain controller must be compatible in order for authentication to be successful (although it is possible for NTLMv2 authentication to pass through an older server to an NTLMv2 domain controller). The result of the configuration and planning required to deploy NTLMv2 is that many hosts just use the default setting (NTLMv1), and NTLMv2 authentication is underutilized.

Instructions for enabling NTLM version 2 are detailed in

Microsoft Knowledge Base Article 239869; briefly, a modification is made to the registry value:

    HKEY_LOCAL_MACHINE/System/CurrentControlSet/Control/LSA/LMCompatibilityLevel

(LMCompatibility on Win9x-based systems). This is a REG_DWORD entry, and can be set to one of the following values:

LevelSent by ClientAccepted by Server0LM
NTLM LM
NTLM
LMv2
NTLMv2 1LM
NTLM LM
NTLM
LMv2
NTLMv2 2NTLM LM
NTLM
LMv2
NTLMv2 3LMv2
NTLMv2 LM
NTLM
LMv2
NTLMv2 4LMv2
NTLMv2 NTLM
LMv2
NTLMv2 5LMv2
NTLMv2 LMv2
NTLMv2

In all levels, NTLM2 session security is supported and negotiated when available (most available documentation indicates that NTLM2 session security is only enabled on levels 1 and above, but it is seen in practice with Level 0 as well). By default, only the LM response is supported on Windows 95 and Windows 98 platforms; installing the Directory Services client makes NTLMv2 available on these hosts as well (and enables the LMCompatibility setting, although only levels 0 and 3 are available).

In Level 2, clients send the NTLM response twice (in both the LM and NTLM response fields). At Level 3 and higher, the LMv2 and NTLMv2 responses replace the LM and NTLM responses, respectively.

When NTLM2 session security has been negotiated (indicated by the "Negotiate NTLM2 Key" flag), the NTLM2 session response can be used in Levels 0, 1, and 2 as a replacement for the weaker LM and NTLM responses. This offers heightened protection over NTLMv1 against server-based precomputed dictionary attacks; the client's response to a given challenge is made variable by adding a random client nonce to the calculation.

The NTLM2 session response is interesting in that it can be negotiated between a client and server that support the newer schemes, even in the presence of an older domain controller that does not. In a typical scenario, the server in an authentication transaction does not actually possess the user's password hash; that is instead held at the domain controller. When a machine is joined to an NT-style domain, it establishes an encrypted, mutually-authenticated channel to the domain controller (colloquially deemed the "NetLogon pipe"). When a client authenticates to the server using the "vanilla" NTLMv1 handshake, the following transactions occur in the background:

The client sends the Type 1 message, containing flags and other information as discussed previously.
The server generates a challenge for the client and sends the Type 2 message containing the negotiated flag set.
The client responds to the challenge, providing the LM/NTLM responses.
The server sends the challenge and client responses over the NetLogon pipe to the domain controller.
The domain controller uses the stored hashes and the challenge given by the server to reproduce the authentication calculations; if they match the responses, the authentication is successful.
The domain controller calculates and sends the session key to the server, which can be used for subsequent signing and sealing operations between the server and the client.

In the case of the NTLM2 Session Response, it is possible that a client and server have been upgraded to allow the newer protocol, but the domain controller has not. To allow for this contingency, the handshake described above is modified slightly as follows:

The client sends the Type 1 message, in this case indicating the "Negotiate NTLM2 Key" flag.
The server generates a challenge for the client and sends the Type 2 message containing the negotiated flag set (also including the "Negotiate NTLM2 Key" flag).
The client responds to the challenge, providing the client nonce in the LM field, and the NTLM2 Session Response in the NTLM field. Note that the latter is exactly the same calculation as the NTLM response, except instead of encrypting the server challenge the client has encrypted the MD5 hash of the server challenge concatenated with the client nonce.
Instead of sending the server challenge directly over the NetLogon pipe to the domain controller, the server sends the MD5 hash of the server challenge concatenated with the client nonce (lifted from the LM response field). Additionally it sends the client responses (as usual).
The domain controller encrypts the challenge field sent by the server using the stored hash as the key and notes that it matches the NTLM response field; hence, the client is successfully authenticated.
The domain controller calculates and sends the normal NTLM User Session Key to the server; the server uses this in a secondary calculation to obtain the NTLM2 Session Response User Session Key (discussed in a subsequent section)

Essentially, this allows upgraded clients and servers to use the NTLM2 Session Response in networks where the domain controller has not yet been upgraded to NTLMv2 (or where the network administrator has not yet configured the LMCompatibilityLevel registry setting to use NTLMv2).

Related to the LMCompatibilityLevel setting are the NtlmMinClientSec and NtlmMinServerSec settings; these specify minimum requirements for NTLM contexts established by the NTLMSSP. Both are REG_WORD entries, and are bitfields specifying a combination of the following NTLM flags:

Negotiate Sign (0x00000010) - Indicates the context must be established with support for message integrity (signing).
Negotiate Seal (0x00000020) - Indicates the context must be established with support for message confidentiality (sealing).
Negotiate NTLM2 Key (0x00080000) - Indicates the context must be established with NTLM2 session security.
Negotiate 128 (0x20000000) - Indicates the context must support at least 128-bit signing/sealing keys.
Negotiate 56 (0x80000000) - Indicates the context must support at least 56-bit signing/sealing keys.

While most of these are more applicable to NTLM2 signing and sealing, the "Negotiate NTLM2 Key" is significant to authentication in that it can prevent sessions from being established with hosts that are unable to negotiate NTLM2 session security. This serves to ensure that the LM and NTLM responses are not sent (requiring that authentication will at least use the NTLM2 Session Response in all cases).

NTLMSSP and SSPI

At this point, we will start to look at how NTLM fits into the "big picture".

Windows provides a security framework known as SSPI - the Security Support Provider interface. This is the Microsoft equivalent of the GSS-API (Generic Security Service Application Program Interface,

RFC 2743), and allows for a very high-level, mechanism-independent means of applying authentication, integrity, and confidentiality primitives. SSPI supports several underlying providers; one of these is the NTLMSSP (NTLM Security Support Provider), which provides the NTLM authentication mechanism we have been discussing thus far. SSPI supplies a flexible API for handling opaque, provider-specific authentication tokens; the NTLM Type 1, Type 2, and Type 3 messages are such tokens, specific to and processed by the NTLMSSP. The API provided by SSPI abstracts away almost all the details of NTLM. The application developer doesn't even have to be aware that NTLM is being used, and another authentication mechanism (such as Kerberos) can be swapped in with little or no changes at the application level.

We aren't going to delve too deeply into the SSPI framework, but this is a good point to look at the SSPI authentication handshake as applied to NTLM:

The client obtains a representation of the credential set for the user via the SSPI AcquireCredentialsHandle function.
The client calls the SSPI InitializeSecurityContext function to obtain an authentication request token (in our case, a Type 1 message). The client sends this token to the server. The return value from the function indicates that authentication will require multiple steps.
The server receives the token from the client, and uses it as input to the AcceptSecurityContext SSPI function. This creates a local security context on the server to represent the client, and yields an authentication response token (the Type 2 message), which is sent to the client. The return value from the function indicates that further information is needed from the client.
The client receives the response token from the server and calls InitializeSecurityContext again, passing the server's token as input. This provides us with another authentication request token (the Type 3 message). The return value indicates that the security context was successfully initialized; the token is sent to the server.
The server receives the token from the client and calls AcceptSecurityContext again, using the Type 3 message as input. The return value indicates the context was successfully accepted; no token is produced, and authentication is complete.

Local Authentication We have alluded to the local authentication sequence at various points in our discussion; having a basic understanding of SSPI, we can look at this scenario in more detail. Local authentication is negotiated through a series of decisions made by the client and server, based on the information in the NTLM messages. It works as follows: The client calls the AcquireCredentialsHandle function, specifying the default credentials by passing in null to the "pAuthData" parameter. This obtains a handle to the credentials of the logged in user for single sign-on. The client calls the SSPI InitializeSecurityContext function to create the Type 1 message. When the default credential handle is supplied, the Type 1 message contains the workstation and domain name of the client. This is indicated by the presence of the "Negotiate Domain Supplied" and "Negotiate Workstation Supplied" flags, and the inclusion of populated Supplied Domain and Supplied Workstation security buffers in the message. The server receives the Type 1 message from the client, and calls AcceptSecurityContext. This creates a local security context on the server to represent the client. The server examines the domain and workstation information sent by the client to determine if the client and server are the same machine. If so, the server initiates local authentication by setting the "Negotiate Local Call" flag in the resultant Type 2 message. The first long in the Context field of the Type 2 message is populated with the "upper" portion of the newly obtained SSPI context handle (specifically, the "dwUpper" field of the SSPI CtxtHandle structure). The second long in the Context field appears to be empty in all cases. (although logically one would assume it should contain the "lower" portion of the context handle). The client receives the Type 2 message from the server and passes it to InitializeSecurityContext. Having noted the presence of the "Negotiate Local Call" flag, the client examines the server context handle to determine if it represents a valid local security context. If the context cannot be validated, authentication proceeds as usual - the appropriate responses are calculated, and included with the domain, workstation, and username in the Type 3 message. If the security context handle from the Type 2 message can be validated, however, no responses are prepared whatsoever. Instead, the default credentials are internally associated with the server context. The resulting Type 3 message is completely empty, containing zero-length security buffers for the responses as well as the username, domain, and workstation. The server receives the Type 3 message and uses it as input to the AcceptSecurityContext function. The server verifies that the security context has been associated with a user; if so, authentication has successfully completed. If the context has not been bound to a user, authentication fails. Datagram Authentication Datagram-style authentication is used to negotiate NTLM over a connectionless transport. While much of the semantics around the messages remain unchanged, there are a few significant differences: SSPI does not create a Type 1 message during the first call to InitializeSecurityContext. Authentication options are offered by the server, rather than requested by the client. Rather than being superfluous (as in connection-oriented authentication), the flags in the Type 3 message carry their usual meanings. During "normal" (connection-oriented) authentication, all options are negotiated in the first transaction between the client and the server, during the exchange of the Type 1 and Type 2 messages. The negotiated settings are "remembered" by the server and applied to the client's Type 3 message. Although most clients send the agreed-upon flags with the Type 3 message, they are not used in connection authentication. In datagram authentication, however, the game changes a bit; to alleviate the server's need to track the negotiated options (which becomes more difficult without a persistent connection), the Type 1 message is removed completely. The server generates a Type 2 message containing all supported flags (as well as the challenge, of course). The client then decides which options it will support, and replies with a Type 3 message containing the responses to the challenge and the set of selected flags. The SSPI handshake sequence for datagram authentication is as follows: The client calls AcquireCredentialsHandle to obtain a representation of the credential set for the user. The client calls InitializeSecurityContext, passing the ISC_REQ_DATAGRAM flag as a context requirement via the fContextReq parameter. This starts the construction of the client's security context, but does not produce a request token (Type 1 message). The server calls the AcceptSecurityContext function, specifying the ASC_REQ_DATAGRAM context requirement flag and passing in a null input token. This creates the local security context and yields an authentication response token (the Type 2 message). This Type 2 message will contain the "Negotiate Datagram Style" flag, as well as all flags supported by the server. This is sent to the client as usual. The client receives the Type 2 message and passes it to InitializeSecurityContext. The client selects appropriate options from those presented by the server (including "Negotiate Datagram Style", which must be set), creates the responses to the challenge, and populates the Type 3 message. The message is then relayed to the server. The server passes the Type 3 message into the AcceptSecurityContext function. The message is processed according to the flags selected by the client, and the context is successfully accepted. When used with SSPI, there is apparently no means of producing a datagram-style Type 1 message. It is interesting to note, however, that we can "induce" datagram semantics at a lower level by subtly manipulating the NTLMSSP tokens to produce our own datagram Type 1 token. This can be achieved by setting the "Negotiate Datagram Style" flag on the Type 1 message produced by the first InitializeSecurityContext call in a connection-oriented SSPI handshake before passing the token to the server. When the modified Type 1 message is passed into the AcceptSecurityContext function, the server will adopt datagram semantics (even though ASC_REQ_DATAGRAM was not specified). This will produce a Type 2 message with the "Negotiate Datagram Style" flag set, but otherwise identical to the connection-oriented message that would normally have been generated; that is, the Type 1 flags sent by the client are considered during the construction of the Type 2 message, rather than simply offering all supported options. The client can then call InitializeSecurityContext with this Type 2 token. Note that the client is still in connection-oriented mode; the Type 3 message produced will ignore the "Negotiate Datagram Style" flag applied to the Type 2 message. The server, however, is enforcing datagram semantics, and will now require the Type 3 flags to be set appropriately. Adding the "Negotiate Datagram Style" flag to the Type 3 message manually before sending it to the server allows the server to successfully call AcceptSecurityContext with the modified token. This results in successful authentication; the "doctored" Type 1 message effectively switches the server into datagram-style authentication, in which the Type 3 flags are observed and enforced. There is no known practical use for this, but it does demonstrate some of the interesting and unexpected behavior that can be observed by strategically manipulating the NTLM messages. Session Security - Signing & Sealing Concepts In addition to the SSPI authentication services, message integrity and confidentiality functionality is provided. This is also implemented by the NTLM Security Support Provider. "Signing" is performed by the SSPI MakeSignature function, which applies a Message Authentication Code (MAC) to a message. This can be verified by the recipient, and provides a strong assurance that the message was not modified in transit. The signature is generated using a secret key, known to the sender and receiver; the MAC can only be verified by a party possessing the key (which in turn provides assurance that the signature was created by the sender). "Sealing" is performed by the SSPI EncryptMessage function. This applies encryption to a message to prevent it from being viewed by a third party in transit; the NTLMSSP uses a variety of symmetric encryption mechanisms (the same key is used to decrypt as to encrypt). The keys used in signing and sealing are established as a by-product of the NTLM authentication process; in addition to verifying a client's identity, the authentication handshake establishes a context between the client and server which includes the key(s) needed to sign and seal messages between the parties. We will discuss the derivation of these keys, and the mechanisms used for signing and sealing by the NTLMSSP. There are numerous key schemes employed during signing and sealing; we will start with an overview of the different types of keys and core session security concepts. The LM User Session Key Used when only the LM response is provided (i.e., with Win9x clients). The LM User Session Key is derived as follows: The 16-byte LM hash (calculated previously) is truncated to 8 bytes. This is null-padded to 16 bytes. This value is the LM User Session Key. As with the LM hash itself, this key only changes in response to a change of password by the user. Note also that only the first 7 password characters have input to the key (see the process for computing the LM Response; the LM User Session Key is the first half of the LM hash). Additionally, the keyspace is actually much smaller, as the LM hash itself is based on the uppercase password. All of these factors combined render the LM User Session Key very weak against attack. The NTLM User Session Key This variant is used when the client sends the NTLM response. The calculation of the key is fairly straightforward: The NTLM hash is obtained (the MD4 digest of the Unicode mixed-case password, calculated previously). The MD4 message-digest algorithm is applied to the NTLM hash, resulting in a 16-byte value. This is the NTLM User Session Key. The NTLM User Session Key is much improved over the LM User Session Key. The password space is larger (it is case-sensitive, rather than converting the password to uppercase); additionally, all password characters have input in the key generation. However, it is still only changed when the user changes his or her password; this makes offline attacks much easier. The LMv2 User Session Key Used when the LMv2 response is sent (but not the NTLMv2 response). Deriving this key is a bit more complicated, but not terribly complex: The NTLMv2 hash is obtained (as calculated previously). The LMv2 client nonce is obtained (used in the LMv2 response). The challenge from the Type 2 message is concatenated with the client nonce. The HMAC-MD5 message authentication code algorithm is applied to this value using the NTLMv2 hash as the key, resulting in a 16-byte output value. The HMAC-MD5 algorithm is applied to this value, again using the NTLMv2 hash as the key. The resulting 16-byte value is the LMv2 User Session Key. The LMv2 User Session Key offers several improvements over the NTLMv1-based keys. It is derived from the NTLMv2 hash (itself derived from the NTLM hash), which is specific to the username and domain/server; additionally, both the server challenge and client nonce provide input to the key calculation. The key calculation can also be stated simply as the HMAC-MD5 digest of the first 16 bytes of the LMv2 response (using the NTLMv2 hash as the key). The NTLMv2 User Session Key Used when the NTLMv2 response is sent. Calculation of this key is very similar to the LMv2 User Session Key: The NTLMv2 hash is obtained (as calculated previously). The NTLMv2 "blob" is obtained (as used in the NTLMv2 response). The challenge from the Type 2 message is concatenated with the blob. The HMAC-MD5 message authentication code algorithm is applied to this value using the NTLMv2 hash as the key, resulting in a 16-byte output value. The HMAC-MD5 algorithm is applied to this value, again using the NTLMv2 hash as the key. The resulting 16-byte value is the NTLMv2 User Session Key. The NTLMv2 User Session Key is quite similar cryptographically to the LMv2 User Session Key. It can be stated as the HMAC-MD5 digest of the first 16 bytes of the NTLMv2 response (using the NTLMv2 hash as the key). The NTLM2 Session Response User Session Key Used when NTLMv1 authentication is employed with NTLM2 session security. This key is derived from the NTLM2 session response information as follows: The NTLM User Session Key is obtained as outlined previously. The session nonce is obtained (discussed previously, this is the concatenation of the Type 2 challenge and the nonce from the NTLM2 session response). The HMAC-MD5 algorithm is applied to the session nonce, using the NTLM User Session Key as the key. The resulting 16-byte value is the NTLM2 Session Response User Session Key. The NTLM2 Session Response User Session Key is notable in that it is calculated between the client and server, rather than at the domain controller. The domain controller derives the NTLM User Session Key and supplies it to the server, as before; if NTLM2 session security has been negotiated with the client, the server then takes the HMAC-MD5 digest of the session nonce using the NTLM User Session Key as the MAC key. The Null User Session Key The Null User Session Key is employed when Anonymous authentication is performed. This one is simple; it's just 16 null bytes ("0x00000000000000000000000000000000"). The Lan Manager Session Key The Lan Manager Session Key is an alternative to the User Session Keys, used to derive keys in NTLM1 signing and sealing when the "Negotiate Lan Manager Key" NTLM flag is set. Calculation of the Lan Manager Session Key is as follows: The 16-byte LM hash (calculated previously) is truncated to 8 bytes. This is padded to 14 bytes with the value "0xbdbdbdbdbdbd". This value is split into two 7-byte halves. These values are used to create two DES keys (one from each 7-byte half). Each of these keys is used to DES-encrypt the first 8 bytes of the LM response (resulting in two 8-byte ciphertext values). These two ciphertext values are concatenated to form a 16-byte value - the Lan Manager Session Key. Note that the Lan Manager Session Key is based on the LM response (rather than simply the LM hash), which means that it will change in response to a different server challenge. This is an advantage over the LM and NTLM User Session Keys, which are based solely on the password hash; the Lan Manager Session Key changes for each authentication operation, while the LM/NTLM User Session Keys remain the same until the user changes his or her password. For this reason, the Lan Manager Session Key is a much stronger scheme than the LM User Session Key (both have a similar key strength, but the Lan Manager Session Key prevents against replay attacks). The NTLM User Session Key has a full 128-bit keyspace, but like the LM User Session Key does not vary on each authentication. Key Exchange When the "Negotiate Key Exchange" flag is negotiated, the client and server will agree upon a "secondary" key, used instead of the session key for signing and sealing. This done as follows: The client selects a random 16-byte key (the secondary key). The session key (either the User Session Key or Lan Manager Session Key, depending on the state of the "Negotiate Lan Manager Key" flag) is used to RC4-encrypt the secondary key. This results in a 16-byte ciphertext value. This value is sent to the server in the "Session Key" field of the Type 3 message. The server receives the Type 3 message and decrypts the value sent by the client (using RC4 with the User Session Key or Lan Manager Session Key). The resulting value is the recovered secondary key, and is used in place of the session key for signing and sealing. Additionally, the key exchange process subtly changes the signing protocol in NTLM2 session security (discussed in a subsequent section). Key Weakening The key used for signing and sealing is "weakened" in accordance with cryptographic export restrictions. The key strength is determined by the "Negotiate 128" and "Negotiate 56" flags. The strength of the final key used is the maximum strength supported by both the client and server; if neither flag is set, the default key length of 40 bits is used. NTLM1 signing and sealing supports 40-bit and 56-bit keys; NTLM2 session security supports 40-bit, 56-bit, and unweakened 128-bit keys. NTLM1 Session Security NTLM1 is the "original" NTLMSSP signing and sealing scheme, used when the "Negotiate NTLM2 Key" flag is not negotiated. Key derivation in this scheme is driven by the following NTLM flags: Negotiate Lan Manager KeyWhen set, the Lan Manager Session Key is used as the basis for the signing and sealing keys (rather than the User Session Key). If not established, the User Session Key will be used for key derivation. Negotiate 56Indicates support for 56-bit keys. If not negotiated, 40-bit keys will be used. This is only applicable in combination with "Negotiate Lan Manager Key"; User Session Keys are not weakened under NTLM1 (as they are already weak). Negotiate Key ExchangeIndicates that key exchange will be performed to negotiate a secondary key for signing and sealing. Master Key Negotiation The first step is negotiation of the 128-bit "master key" from which the final signing and sealing key will be derived. This is driven by the "Negotiate Lan Manager Key" NTLM flag; if set, the Lan Manager Session Key will be used as the master key. Otherwise, the appropriate User Session Key is employed. As an example, consider our example user with the password "SecREt01". If the "Negotiate Lan Manager" key is not set, and an NTLM response was provided in the Type 3 message, the NTLM User Session Key will be selected as the master key. This is calculated by taking the MD4 digest of the NTLM hash (which is itself the MD4 hash of the Unicode password): 0x3f373ea8e4af954f14faa506f8eebdc4 Key Exchange If the "Negotiate Key Exchange" flag is set, the client will populate the "Session Key" field in the Type 3 message with a new master key, RC4-encrypted with the previously selected master key. The server will decrypt this value to receive the new master key. For example, assume that the client selects the random master key "0xf0f0aabb00112233445566778899aabb". The client will encrypt this value using RC4 with the previously negotiated master key ("0x3f373ea8e4af954f14faa506f8eebdc4") to obtain the value: 0x1d3355eb71c82850a9a2d65c2952e6f3 This is sent to the server in the "Session Key" field of the Type 3 message. The server RC4-decrypts this value using the old master key to recover the new master key selected by the client ("0xf0f0aabb00112233445566778899aabb"). Key Weakening Finally, the key is weakened to comply with export restrictions. NTLM1 supports 40-bit and 56-bit keys. If the "Negotiate 56" NTLM flag is set, the 128-bit master key will be weakened to 56-bits; otherwise, it will be weakened to 40-bits. Note that key weakening is only employed under NTLM1 when the Lan Manager Session Key is used ("Negotiate Lan Manager Key" is set). The LM and NTLM User Session Keys are based on the password hashes, rather than the responses; a given password will always result in the same User Session Key under NTLM1. Weakening was apparently not deemed necessary, since the User Session Key can be easily recovered given a user's password hash. The process for key weakening under NTLM1 is as follows: To produce a 56-bit key, the master key is truncated to 7 bytes (56 bits) and the byte value "0xa0" is appended. To produce a 40-bit key, the master key is truncated to 5 bytes (40 bits) and the three-byte value "0xe538b0" is appended. Using the master key "0x0102030405060708090a0b0c0d0e0f00" as an example, the 40-bit key used for signing and sealing would be "0x0102030405e538b0". If 56-bit keys are negotiated, the final key would be "0x01020304050607a0". Signing Once the key has been negotiated it can be used to produce digital signatures, providing message integrity. Support for signing is indicated by the presence of the "Negotiate Sign" NTLM flag. NTLM1 signing (as done by the SSPI MakeSignature function) is performed as follows: An RC4 cipher is initialized using the previously negotiated key. This is done once (before the first signing operation), and the keystream is never reset. The CRC32 checksum of the message is calculated; this is represented as a long (32-bit little-endian value). A sequence number is obtained; this starts at zero and is incremented after each message is signed. The number is represented as a long. Four zero bytes are concatenated with the CRC32 value and sequence number to obtain a 12-byte value ("0x00000000" + CRC32(message) + sequenceNumber). This value is encrypted using the previously initialized RC4 cipher. The first four bytes of the ciphertext result are overwritten with a pseudorandom counter value (the actual value used is insignificant). A version number ("0x01000000") is concatenated with the result from the previous step to form the signature. As an example, assume that we are signing the message "jCIFS" (hexadecimal "0x6a43494653") using the 40-bit key from the previous example: The CRC32 checksum is calculated (in little-endian hexadecimal, "0xa0310bb7"). A sequence number is obtained. Since this is the first message we have signed, the sequence number is zero ("0x00000000"). Four zero bytes are concatenated with the CRC32 value and sequence number to obtain a 12-byte value ("0x00000000a0310bb700000000"). This value is RC4-encrypted using our key ("0x0102030405e538b0"); this yields the ciphertext "0xecbf1ced397420fe0e5a0f89". The first four bytes are overwritten with a counter value; using "0x78010900" gives "0x78010900397420fe0e5a0f89". The version stamp is concatenated with the result to form the final signature: 0x0100000078010900397420fe0e5a0f89 The next message signed would receive the sequence number 1; also, note again that the RC4 keystream initialized with the first signing is not reset for subsequent signatures. NTLM2 Session Security NTLM2 is a newer signing and sealing scheme, used when the "Negotiate NTLM2 Key" flag has been established. Key derivation in this scheme is driven by the following NTLM flags: Negotiate NTLM2 KeyIndicates support for NTLM2 session security. Negotiate 56Indicates support for 56-bit keys. If neither this flag nor "Negotiate 128" are specified, 40-bit keys will be used. Negotiate 128Indicates support for 128-bit keys. If neither this flag nor "Negotiate 56" are specified, 40-bit keys will be used. Negotiate Key ExchangeIndicates that key exchange will be performed to negotiate a secondary base key for signing and sealing. Master Key Negotiation The User Session Key is always used as the base master key in NTLM2 signing and sealing. When NTLMv2 authentication is used, either the LMv2 or NTLMv2 User Session Key will be employed as the master key. When NTLMv1 authentication is used with NTLM2 session security, the NTLM2 Session Response User Session Key is used as the master key. Note that the User Session Keys used in NTLM2 are significantly stronger than either their NTLM1 counterparts or the Lan Manager Session Key, as they incorporate both the server challenge and client nonce. Key Exchange Key exchange is performed as previously discussed for NTLM1. The client selects a secondary master key, RC4-encrypts it with the base master key, and sends the ciphertext value to the server in the Type 3 "Session Key" field. This is indicated by the presence of the "Negotiate Key Exchange" flag. Key Weakening Key weakening in NTLM2 is performed simply by truncating the master key (or secondary master key, if key exchange is performed) to the appropriate length; for example, the master key "0xf0f0aabb00112233445566778899aabb" would be weakened to 40 bits as "0xf0f0aabb00", and 56 bits as "0xf0f0aabb001122". Note that 128-bit keys are supported under NTLM2; in this case, the master key is used directly in the generation of subkeys (with no weakening performed). The master key is only weakened under NTLM2 when generating the sealing subkeys; the full 128-bit master key is always used in the generation of signing keys. Signing Signing support is again indicated by the "Negotiate Sign" NTLM flag. Signing by the client is done using the Client Signing Key; the server signs messages using the Server Signing Key. Signing keys are generated from the unweakened master key (as discussed previously). NTLM2 signing (as done by the SSPI MakeSignature function) is performed as follows: A sequence number is obtained; this starts at zero and is incremented after each message is signed. The number is represented as a long (32-bit little-endian value). The sequence number is concatenated with the message; the HMAC-MD5 message authentication code algorithm is applied to this value, using the appropriate Signing Key. This yields a 16-byte value. If Key Exchange has been negotiated, an RC4 cipher is initialized using the appropriate Sealing key. This is done once (during the first operation), and the keystream is never reset. The first eight bytes from the HMAC result are encrypted using this RC4 cipher. If Key Exchange has not been negotiated, this sealing operation is omitted. A version number ("0x01000000") is concatenated with the result from the previous step and the sequence number to form the signature. As an example, assume that we are signing the message "jCIFS" (hexadecimal "0x6a43494653") on the client, using the master key "0x0102030405060708090a0b0c0d0e0f00". This is concatenated with the client-to-server signing constant, and MD5 is applied to yield the Client Signing Key ("0xf7f97a82ec390f9c903dac4f6aceb132") and Client Sealing Key ("0x2785f595293f3e2813439d73a223810d"); these are used as follows to sign the message: A sequence number is obtained. Since this is the first message we have signed, the sequence number is zero ("0x00000000"). The sequence number is concatenated with the message: 0x000000006a43494653 HMAC-MD5 is applied using the Client Signing Key ("0xf7f97a82ec390f9c903dac4f6aceb132"). This results in the 16-byte value "0x0a003602317a759a720dc9c7a2a95257". An RC4 cipher is initialized with our sealing key ("0x2785f595293f3e2813439d73a223810d"). The first eight bytes of the previous result are passed through the cipher, yielding the ciphertext "0xe37f97f2544f4d7e". The version stamp is concatenated with the result from the previous step and the sequence number to form the final signature: 0x01000000e37f97f2544f4d7e00000000 Sealing The "Negotiate Seal" NTLM flag again indicates support for message confidentiality in NTLM2. NTLM2 sealing (as done by the SSPI EncryptMessage function) is performed as follows: An RC4 cipher is initialized using the appropriate sealing key (depending on whether the client or server is performing sealing). This is done once (before the first sealing operation), and the keystream is never reset. The message is encrypted using the RC4 cipher; this produces the sealed ciphertext. A signature for the message is produced, as described previously, and placed in the security trailer buffer. Note that the RC4 cipher used in the signing operation has already been initialized (in the previous steps); it is not reset for the signing operation. As an example, assume that we are sealing the message "jCIFS" (hexadecimal "0x6a43494653") on the client, using the master key "0x0102030405060708090a0b0c0d0e0f00". As in our previous example, we generate the Client Signing Key ("0xf7f97a82ec390f9c903dac4f6aceb132") using the unweakened master key. We also need to generate the Client Sealing Key; we will assume that 40-bit weakening has been negotiated. We concatenate the weakened master key ("0x0102030405") with the client-to-server sealing constant, and MD5 is applied to yield the Client Sealing Key ("0x6f0d99535033951cbe499cd1914fe9ee"). The following procedure is used to seal the message: An RC4 cipher is initialized with our Client Sealing Key ("0x6f0d99535033951cbe499cd1914fe9ee"). Our message is passed through the RC4 cipher, yielding the ciphertext "0xcf0eb0a939". This is the sealed message. A sequence number is obtained. Since this is the first signing, the sequence number is zero ("0x00000000"). The sequence number is concatenated with the message: 0x000000006a43494653 HMAC-MD5 is applied using the Client Signing Key ("0xf7f97a82ec390f9c903dac4f6aceb132"). This results in the 16-byte value "0x0a003602317a759a720dc9c7a2a95257". The first eight bytes of this value are passed through the sealing cipher, resulting in the ciphertext "0x884b14809e53bfe7". The version stamp is concatenated with the result and the sequence number to form the final signature, which is placed in the security trailer buffer: 0x01000000884b14809e53bfe700000000 A hexadecimal dump of the entire sealed structure would be: 0xcf0eb0a93901000000884b14809e53bfe700000000 Miscellaneous Session Security Topics There are a couple of other session security topics which don't really fit anywhere else: Datagram Signing & Sealing "Dummy" Signing Datagram Signing & Sealing This is used when a datagram context has been established (indicated by the datagram authentication handshake and the presence of the "Negotiate Datagram Style" flag). The semantics regarding datagram session security are a bit different; signing can begin on the client immediately after the first call to the SSPI InitializeSecurityContext function (i.e., before any communication to the server). This implies a prearranged signing and sealing scheme (as signatures can be created before any options are negotiated with the server). Datagram session security is based on 40-bit Lan Manager Session Key NTLM1 with key exchange (although there may be some means of predetermining a stronger scheme through the registry). The sequence number is not incremented in datagram mode; it is fixed at zero, and each signature reflects this. Also, the RC4 keystream is reset for each signing or sealing operation. This is significant, in that messages are potentially susceptible to known plaintext attacks. Appendix A: Links and References Note that due to the highly dynamic and transient nature of the Web, these may or may not be available. The jCIFS Project Home Page "Dummy" Signing This is used if the SSPI context was initialized without specifying support for message integrity. If the "Negotiate Always Sign" NTLM flag is established, calls to MakeSignature will succeed, returning the constant "signature": 0x01000000000000000000000000000000 Calls to EncryptMessage succeed normally (including the "real" signature in the security trailer buffer). If "Negotiate Always Sign" is not negotiated, both signing and sealing will fail. Subkey Generation Under NTLM2, up to four subkeys are established; the master key is never actually used to sign or seal messages. The subkeys are generated as follows: The 128-bit (unweakened) master key is concatenated with the null-terminated ASCII constant string: session key to client-to-server signing key magic constant In hexadecimal, this constant is: 0x73657373696f6e206b657920746f2063 6c69656e742d746f2d73657276657220 7369676e696e67206b6579206d616769 6320636f6e7374616e7400 The line breaks in the above are for display purposes only. The MD5 message-digest algorithm is applied to this, resulting in a 16-byte value. This is the Client Signing Key, used by the client to create signatures for messages. The unweakened master key is concatenated with the null-terminated ASCII constant string: session key to server-to-client signing key magic constant In hexadecimal, this constant is: 0x73657373696f6e206b657920746f2073 65727665722d746f2d636c69656e7420 7369676e696e67206b6579206d616769 6320636f6e7374616e7400 The MD5 digest of this is taken, resulting in the 16-byte Server Signing Key. This is used by the server to create signatures for messages. The weakened (depending on whether 40-bit, 56-bit, or 128-bit encryption is negotiated) master key is concatenated with the null-terminated ASCII constant string: session key to client-to-server sealing key magic constant In hexadecimal, this constant is: 0x73657373696f6e206b657920746f2063 6c69656e742d746f2d73657276657220 7365616c696e67206b6579206d616769 6320636f6e7374616e7400 The MD5 digest is taken to obtain the 16-byte Client Sealing Key. This is used by the client to encrypt messages. The weakened master key is concatenated with the null-terminated ASCII constant string: session key to server-to-client sealing key magic constant In hexadecimal, this constant is: 0x73657373696f6e206b657920746f2073 65727665722d746f2d636c69656e7420 7365616c696e67206b6579206d616769 6320636f6e7374616e7400 The MD5 digest algorithm is applied, yielding the 16-byte Server Sealing Key. This key is used by the server to encrypt messages. NTLM2 Key Derivation Key derivation in NTLM2 is a four-step process: Master key negotiation Key exchange Key weakening Subkey generation Sealing In addition to message integrity, message confidentiality is provided via sealing. The "Negotiate Seal" NTLM flag indicates support for sealing. Under SSPI with the NTLM provider, sealing is always performed in combination with signing (sealing a message simultaneously generates a signature); the same RC4 keystream is used for both signing and sealing. NTLM1 sealing (as done by the SSPI EncryptMessage function) is performed as follows: An RC4 cipher is initialized using the previously negotiated key. This is done once (before the first sealing operation), and the keystream is never reset. The message is encrypted using the RC4 cipher; this produces the sealed ciphertext. A signature for the message is produced, as described previously, and placed in the security trailer buffer. As an example, consider the sealing of the message "jCIFS" ("0x6a43494653") using the 40-bit key "0x0102030405e538b0": An RC4 cipher is initialized with our key ("0x0102030405e538b0"). Our message is passed through the RC4 cipher, yielding the ciphertext "0x86fc55abca". This is the sealed message. The CRC32 checksum of our message is calculated (in little-endian hexadecimal, "0xa0310bb7"). A sequence number is obtained. Since this is the first signing, the sequence number is zero ("0x00000000"). Four zero bytes are concatenated with the CRC32 value and sequence number to obtain a 12-byte value ("0x00000000a0310bb700000000"). This value is RC4-encrypted using the keystream from our cipher; this yields the ciphertext "0x452b490efa3e828bcc8affc3". The first four bytes are overwritten with a counter value; using "0x78010900" gives "0x78010900fa3e828bcc8affc3". The version stamp is concatenated with the result to form the final signature, which is placed in the security trailer buffer: 0x0100000078010900fa3e828bcc8affc3 A hexadecimal dump of the entire sealed structure would be: 0x86fc55abca0100000078010900fa3e828bcc8affc3 NTLM1 Key Derivation Deriving NTLM1 keys is essentially a three-step process: Master key negotiation Key exchange Key weakening The User Session Key This is the basic key type employed in session security. There are many variants: The LM User Session Key The NTLM User Session Key The LMv2 User Session Key The NTLMv2 User Session Key The NTLM2 Session Response User Session Key The method of derivation used depends on the responses sent in the Type 3 message. These variants and their calculations are outlined below.: http://jcifs.samba.org/
jCIFS is an open-source Java implementation of CIFS/SMB. The information presented in this article was used as the basis for the jCIFS NTLM authentication implementation. jCIFS provides support for both the client and server sides of the NTLM HTTP authentication scheme, as well as non-protocol-specific NTLM utility classes.

The Samba Home Page: http://www.samba.org/
Samba is an open-source CIFS/SMB server and client. Implements NTLM authentication and session security, and a reference for much of this document.

Implementing CIFS: The Common Internet FileSystem: http://ubiqx.org/cifs/
A highly informative online book by Christopher R. Hertel. Especially relevant to this discussion is the section on authentication.

The Open Group ActiveX Core Technology Reference (Chapter 11, "NTLM"): http://www.opengroup.org/comsource/techref2/NCH1222X.HTM
Closest thing to an "official" reference on NTLM. Unfortunately, also rather old and not terribly accurate.

The Security Support Provider Interface: http://www.microsoft.com/windows2000/techinfo/howitworks/security/sspi2000.asp
A whitepaper discussing application development using the SSPI.

NTLM Authentication Scheme for HTTP: http://www.innovation.ch/java/ntlm.html
Informative discussion on the NTLM HTTP authentication mechanism.

Squid NTLM Authentication Project: http://squid.sourceforge.net/ntlm/
Project to provide NTLM HTTP authentication to the Squid proxy server.

Jakarta Commons HttpClient: http://jakarta.apache.org/commons/httpclient/
An open-source Java HTTP client which provides support for the NTLM HTTP authentication scheme.

The GNU Crypto Project: http://www.gnu.org/software/gnu-crypto/
An open-source Java Cryptography Extension provider supplying an implementation of the MD4 message-digest algorithm.

RFC 1320 - The MD4 Message-Digest Algorithm: http://www.ietf.org/rfc/rfc1320.txt
Specification and reference implementation for the MD4 digest (used to calculate the NTLM password hash).

RFC 1321 - The MD5 Message-Digest Algorithm: http://www.ietf.org/rfc/rfc1321.txt
Specification and reference implementation for the MD5 digest (used to calculate the NTLM2 session response).

RFC 2104 - HMAC: Keyed-Hashing for Message Authentication: http://www.ietf.org/rfc/rfc2104.txt
Specification and reference implementation for the HMAC-MD5 algorithm (used in the calculation of the NTLMv2/LMv2 responses).

How to Enable NTLM 2 Authentication: http://support.microsoft.com/default.aspx?scid=KB;en-us;239869
Describes how to enable negotiation of NTLMv2 authentication and enforce NTLM security flags.

Microsoft SSPI Function Documentation: http://windowssdk.msdn.microsoft.com/en-us/library/ms717571.aspx#sspi_functions
Provides an overview of the Security Support Provider Interface (SSPI) and related functions.

Appendix B: Application Protocol Usage of NTLM

This section examines the use of NTLM authentication within some of Microsoft's network protocol implementations.

NTLM HTTP Authentication

Microsoft has established the proprietary "NTLM" authentication scheme for HTTP to provide integrated authentication to IIS web servers. This authentication mechanism allows clients to access resources using their Windows credentials, and is typically used within corporate environments to provide single sign-on functionality to intranet sites. Historically, NTLM authentication was only supported by Internet Explorer; recently, however, support has been added to various other user agents.

The NTLM HTTP authentication mechanism works as follows:

The client requests a protected resource from the server:
```
    GET /index.html HTTP/1.1
```
The server responds with a 401 status, indicating that the client must authenticate. "NTLM" is presented as a supported authentication mechanism via the "WWW-Authenticate" header. Typically, the server closes the connection at this time:
```
    HTTP/1.1 401 Unauthorized    WWW-Authenticate: NTLM    Connection: close
```
Note that Internet Explorer will only select NTLM if it is the first mechanism offered; this is at odds with RFC 2616, which states that the client must select the strongest supported authentication scheme.
The client resubmits the request with an "Authorization" header containing a Type 1 message parameter. The Type 1 message is Base-64 encoded for transmission. From this point forward, the connection is kept open; closing the connection requires reauthentication of subsequent requests. This implies that the server and client must support persistent connections, via either the HTTP 1.0-style "Keep-Alive" header or HTTP 1.1 (in which persistent connections are employed by default). The relevant request headers appear as follows (the line break in the "Authorization" header below is for display purposes only, and is not present in the actual message):
```
    GET /index.html HTTP/1.1    Authorization: NTLM TlRMTVNTUAABAAAABzIAAAYABgArAAAACwALACAAAABXT1    JLU1RBVElPTkRPTUFJTg==
```

The server replies with a 401 status containing a Type 2 message in the "WWW-Authenticate" header (again, Base-64 encoded). This is shown below (the line breaks in the "WWW-Authenticate" header are for editorial clarity only, and are not present in the actual header).

    HTTP/1.1 401 Unauthorized    WWW-Authenticate: NTLM TlRMTVNTUAACAAAADAAMADAAAAABAoEAASNFZ4mrze8    AAAAAAAAAAGIAYgA8AAAARABPAE0AQQBJAE4AAgAMAEQATwBNAEEASQBOAAEADABTA    EUAUgBWAEUAUgAEABQAZABvAG0AYQBpAG4ALgBjAG8AbQADACIAcwBlAHIAdgBlAHI    ALgBkAG8AbQBhAGkAbgAuAGMAbwBtAAAAAAA=

The client responds to the Type 2 message by resubmitting the request with an "Authorization" header containing a Base-64 encoded Type 3 message (again, the line breaks in the "Authorization" header below are for display purposes only):

    GET /index.html HTTP/1.1    Authorization: NTLM TlRMTVNTUAADAAAAGAAYAGoAAAAYABgAggAAAAwADABAAA    AACAAIAEwAAAAWABYAVAAAAAAAAACaAAAAAQIAAEQATwBNAEEASQBOAHUAcwBlAHIA    VwBPAFIASwBTAFQAQQBUAEkATwBOAMM3zVy9RPyXgqZnr21CfG3mfCDC0+d8ViWpjB    wx6BhHRmspst9GgPOZWPuMITqcxg==

Finally, the server validates the responses in the client's Type 3 message and allows access to the resource.
```
    HTTP/1.1 200 OK
```

This scheme differs from most "normal" HTTP authentication mechanisms, in that subsequent requests over the authenticated connection are not themselves authenticated; NTLM is connection-oriented, rather than request-oriented. So a second request for "/index.html" would not carry any authentication information, and the server would request none. If the server detects that the connection to the client has been dropped, a request for "/index.html" would result in the server reinitiating the NTLM handshake.

A notable exception to the above is the client's behavior when submitting a POST request (typically employed when the client is sending form data to the server). If the client determines that the server is not the local host, the client will initiate reauthentication for POST requests over the active connection. The client will first submit an empty POST request with a Type 1 message in the "Authorization" header; the server responds with the Type 2 message (in the "WWW-Authenticate" header as shown above). The client then resubmits the POST with the Type 3 message, sending the form data with the request.

The NTLM HTTP mechanism can also be used for HTTP proxy authentication. The process is similar, except:

The server uses the 407 response code (indicating proxy authentication required) rather than 401.
The client's Type 1 and 3 messages are sent in the "Proxy-Authorization" request header, rather than the "Authorization" header.
The server's Type 2 challenge is sent in the "Proxy-Authenticate" response header (instead of "WWW-Authenticate").

With Windows 2000, Microsoft introduced the "Negotiate" HTTP authentication mechanism. While primarily aimed at providing a means of authenticating the user against Active Directory via Kerberos, it is backward-compatible with the NTLM scheme. When the Negotiate mechanism is used in "legacy" mode, the headers passed between the client and server are identical, except "Negotiate" (rather than "NTLM") is indicated as the mechanism name.

NTLM POP3 Authentication

Microsoft's Exchange server provides an NTLM authentication mechanism for the POP3 protocol. This is a proprietary extension used with the POP3 AUTH command as documented in

RFC 1734. On the client side, this mechanism is supported by Outlook and Outlook Express, and is called "Secure Password Authentication".

The POP3 NTLM authentication handshake occurs during the POP3 "authorization" state, and works as follows:

The client may request a list of supported authentication mechanisms by sending the AUTH command with no arguments:
```
    AUTH
```
The server responds with a success message, followed by the list of supported mechanisms; this list should include "NTLM", and is terminated by a line containing a single period (".").
```
    +OK The operation completed successfully.    NTLM    .
```
The client initiates NTLM authentication by sending an AUTH command specifying NTLM as the authentication mechanism:
```
    AUTH NTLM
```
The server responds with a success message as shown below. Note that there is a space between the "+" and the "OK"; RFC 1734 states that the server should reply with a challenge, but NTLM requires the Type 1 message from the client. So the server sends a "non-challenge", which is basically the message "OK".
```
    + OK
```

The client then sends the Type 1 message, Base-64 encoded for transmission:

    TlRMTVNTUAABAAAABzIAAAYABgArAAAACwALACAAAABXT1JLU1RBVElPTkRPTUFJTg==

The server replies with the Type 2 challenge message (again, Base-64 encoded). This is send in the challenge format specified by RFC 1734 ("+", followed by a space, followed by the challenge message). This is shown below; the line breaks are for editorial clarity and are not present in the server's reply:
```
    + TlRMTVNTUAACAAAADAAMADAAAAABAoEAASNFZ4mrze8AAAAAAAAAAGIAYgA8AAAA    RABPAE0AQQBJAE4AAgAMAEQATwBNAEEASQBOAAEADABTAEUAUgBWAEUAUgAEABQAZA    BvAG0AYQBpAG4ALgBjAG8AbQADACIAcwBlAHIAdgBlAHIALgBkAG8AbQBhAGkAbgAu    AGMAbwBtAAAAAAA=
```

The client calculates and sends the Base-64 encoded Type 3 response (the line breaks below are for display purposes only):

    TlRMTVNTUAADAAAAGAAYAGoAAAAYABgAggAAAAwADABAAAAACAAIAEwAAAAWABYAVA    AAAAAAAACaAAAAAQIAAEQATwBNAEEASQBOAHUAcwBlAHIAVwBPAFIASwBTAFQAQQBU    AEkATwBOAMM3zVy9RPyXgqZnr21CfG3mfCDC0+d8ViWpjBwx6BhHRmspst9GgPOZWP    uMITqcxg==

The server validates the response and indicates the result of authentication:
```
    +OK User successfully logged on
```

After successful authentication has occurred, the POP3 session enters the "transaction" state, allowing messages to be retrieved by the client. RFC 1730; the NTLM mechanism is a proprietary extension provided by Exchange and supported by the Outlook client family.

NTLM IMAP Authentication

Exchange provides an IMAP authentication mechanism similar in form to the POP3 mechanism previously discussed. IMAP authentication is documented in

The handshake sequence is similar to the POP3 mechanism:

The server may indicate support for the NTLM authentication mechanism in the capability response. Upon connecting to the IMAP server, the client would request the list of server capabilities:
```
    0000 CAPABILITY
```
The server responds with the list of supported capabilities; the NTLM authentication extension is indicated by the presence of the string "AUTH=NTLM" in the server's reply:
```
    * CAPABILITY IMAP4 IMAP4rev1 IDLE LITERAL+ AUTH=NTLM    0000 OK CAPABILITY completed.
```
The client initiates NTLM authentication by sending an AUTHENTICATE command specifying NTLM as the authentication mechanism:
```
    0001 AUTHENTICATE NTLM
```
The server responds with an empty challenge, consisting simply of a "+":
```
    +
```

The client then sends the Type 1 message, Base-64 encoded for transmission:

    TlRMTVNTUAABAAAABzIAAAYABgArAAAACwALACAAAABXT1JLU1RBVElPTkRPTUFJTg==

The server replies with the Type 2 challenge message (again, Base-64 encoded). This is send in the challenge format specified by RFC 1730 ("+", followed by a space, followed by the challenge message). This is shown below; the line breaks are for editorial clarity and are not present in the server's reply:
```
    + TlRMTVNTUAACAAAADAAMADAAAAABAoEAASNFZ4mrze8AAAAAAAAAAGIAYgA8AAAA    RABPAE0AQQBJAE4AAgAMAEQATwBNAEEASQBOAAEADABTAEUAUgBWAEUAUgAEABQAZA    BvAG0AYQBpAG4ALgBjAG8AbQADACIAcwBlAHIAdgBlAHIALgBkAG8AbQBhAGkAbgAu    AGMAbwBtAAAAAAA=
```

The client calculates and sends the Base-64 encoded Type 3 response (the line breaks below are for display purposes only):

    TlRMTVNTUAADAAAAGAAYAGoAAAAYABgAggAAAAwADABAAAAACAAIAEwAAAAWABYAVA    AAAAAAAACaAAAAAQIAAEQATwBNAEEASQBOAHUAcwBlAHIAVwBPAFIASwBTAFQAQQBU    AEkATwBOAMM3zVy9RPyXgqZnr21CfG3mfCDC0+d8ViWpjBwx6BhHRmspst9GgPOZWP    uMITqcxg==

The server validates the response and indicates the result of authentication:
```
    0001 OK AUTHENTICATE NTLM completed.
```

After authentication has completed, the IMAP session enters the authenticated state.

NTLM SMTP Authentication

In addition to the NTLM authentication mechanisms provided for POP3 and IMAP, Exchange provides similar functionality for the SMTP protocol. This allows NTLM authentication of users sending outgoing mail messages. This is a proprietary extension used with the SMTP AUTH command (documented in

RFC 2554).

The SMTP NTLM authentication handshake operates as follows:

The server may indicate support for NTLM as an authentication mechanism in the EHLO reply. Upon connecting to the SMTP server, the client would send the initial EHLO message:
```
    EHLO client.example.com
```
The server responds with the list of supported extensions; the NTLM authentication extension is indicated by its presence in the list of AUTH mechanisms as shown below. Note that the AUTH list is sent twice (once with an "=" and once without). The "AUTH=" form was apparently specified in a draft of the RFC; sending both forms ensures that clients implemented against this draft are supported.
```
    250-server.example.com Hello [10.10.2.20]    250-HELP    250-AUTH LOGIN NTLM    250-AUTH=LOGIN NTLM    250 SIZE 10240000
```
The client initiates NTLM authentication by sending an AUTH command specifying NTLM as the authentication mechanism and providing the Base-64 encoded Type 1 message as a parameter:
```
    AUTH NTLM TlRMTVNTUAABAAAABzIAAAYABgArAAAACwALACAAAABXT1JLU1RBVElPTkRPTUFJTg==
```
According to RFC 2554, the client may opt not to send the initial response parameter (instead merely sending "AUTH NTLM" and waiting for an empty server challenge before replying with the Type 1 message). However, this did not appear to work properly when tested against Exchange.

The server replies with a 334 response containing the Type 2 challenge message (again, Base-64 encoded). This is shown below; the line breaks are for editorial clarity and are not present in the server's reply:

    334 TlRMTVNTUAACAAAADAAMADAAAAABAoEAASNFZ4mrze8AAAAAAAAAAGIAYgA8AAAA    RABPAE0AQQBJAE4AAgAMAEQATwBNAEEASQBOAAEADABTAEUAUgBWAEUAUgAEABQAZA    BvAG0AYQBpAG4ALgBjAG8AbQADACIAcwBlAHIAdgBlAHIALgBkAG8AbQBhAGkAbgAu    AGMAbwBtAAAAAAA=

The client calculates and sends the Base-64 encoded Type 3 response (the line breaks below are for display purposes only):

    TlRMTVNTUAADAAAAGAAYAGoAAAAYABgAggAAAAwADABAAAAACAAIAEwAAAAWABYAVA    AAAAAAAACaAAAAAQIAAEQATwBNAEEASQBOAHUAcwBlAHIAVwBPAFIASwBTAFQAQQBU    AEkATwBOAMM3zVy9RPyXgqZnr21CfG3mfCDC0+d8ViWpjBwx6BhHRmspst9GgPOZWP    uMITqcxg==

The server validates the response and indicates the result of authentication:
```
    235 NTLM authentication successful.
```

After authenticating, the client is able to send messages normally.

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the LM User Session Key

Demonstration of NTLMv1 authentication with LM User Session Key NTLM1 signing and sealing (without key exchange). NTLM response is manually removed from the Type 3 message to force the server-side context to use the LM User Session Key.

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4e544c4d535350000100000037820000000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 message37820000            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000358281006da297169f7aa9c20000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35828100            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)6da297169f7aa9c2    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message; NTLM responseis removed to force usage of the LM User Session Key:4e544c4d5353500003000000180018004000000000000000000000000c000c005800000008000800640000000c000c006c0000000000000000000000358280002e17884ea16177e2b751d53b5cc756c3cd57cdfd6e3bf8b954004500530054004e00540074006500730074004d0045004d004200450052004e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180040000000    LM/LMv2 Response (length 24, offset 64)0000000000000000    NTLM/NTLMv2 Response (empty, removed)0c000c0058000000    Domain Name header (length 12, offset 88)0800080064000000    User Name header (length 8, offset 100)0c000c006c000000    Workstation Name header (length 12, offset 108)0000000000000000    Session Key header (empty)35828000            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)2e17884ea16177e2b751d53b5cc756c3cd57cdfd6e3bf8b9    LM/LMv2 Response54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35828101    flags0000000000000000f8290900f8290900782a0900782a09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f28010000624aac413795cdc10000000000000000    outbound signing key624aac413795cdc10000000000000000    inbound verifying key624aac413795cdc10000000000000000    outbound encrypting key624aac413795cdc10000000000000000    inbound decrypting 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    "TESTNT/test"lmHash = lmEncrypt(password, "KGS!@#$%") = 0x624aac413795cdc1ff17365faf1ffe89LMUserSessionKey = trunc(lmHash) = 0x624aac413795cdc10000000000000000Key is *not* weakened (NTLM1 only weakens Lan Manager Session Keys).Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:0100000090010700cacc888006466cb5CRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0xdd0e70b1cacc888006466cb5version num + first 4 bytes overwritten with counter value (0x90010700 here):0100000090010700cacc888006466cb5 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:48793abbf0145ddb01000000a0030700e286c6021ffc374209613b9790f7d40e0100000088030700fb8e614d1cf2284csame RC4 cipher is used from previous signing operation (i.e., not reset):RC4(0x0102030405060708) = sealed message = 0x48793abbf0145ddbtrailer buffer gets signature; again uses same RC4 cipher(sequence number is now 1 because of previous signing):RC4(0x00000000c588ca3f01000000) = 0x623bc698e286c6021ffc3742version num + first 4 bytes overwritten w/counter (0xa0030700):01000000a0030700e286c6021ffc3742 = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0x09613b9790f7d40etrailer buffer signature with sequence 2:RC4(0x00000000c588ca3f02000000) = 0x85433470fb8e614d1cf2284cversion num + first 4 bytes overwritten w/counter (0x88030700)0100000088030700fb8e614d1cf2284c = trailer signature

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 56-bit Lan Manager Session Key

Demonstration of NTLMv1 authentication with 56-bit Lan Manager Session Key NTLM1 signing and sealing (without key exchange).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)4e544c4d5353500001000000b7820080000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb7820080            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate 56                   (0x80000000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000b5828180c77c1fcdb77ad0420000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)b5828180            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)    Negotiate 56                   (0x80000000)c77c1fcdb77ad042    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c00540000000000000090000000b582808054004500530054004e00540074006500730074004d0045004d004200450052002e1580af209c1579bbd95a0c9568e2a7455764064cd8ff8c75791b1820178018c9d00365a5dedfaa455ef8c3b3ad1c1c4e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)0000000090000000    Session Key header (empty)b5828080            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)    Negotiate 56                   (0x80000000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")2e1580af209c1579bbd95a0c9568e2a7455764064cd8ff8c    LM/LMv2 Response75791b1820178018c9d00365a5dedfaa455ef8c3b3ad1c1c    NTLM/NTLMv2 Response--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpperb5828181    flags, also has an unknown flag 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    "TESTNT/test"lmHash = lmEncrypt(password, "KGS!@#$%") = 0x624aac413795cdc1ff17365faf1ffe89trunc(lmHash + pad) = 0x624aac413795cdc1bdbdbdbdbdbdlmResponse[0-7] = 0x2e1580af209c1579LanManagerSessionKey =    lmEncrypt(0x624aac413795cdc1bdbdbdbdbdbd, 0x2e1580af209c1579) =        0xf41c7848bec59daa4cfe52156645f77bKey is weakened to 56-bit w/0xa0 = 0xf41c7848bec59da0Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:0100000090010700598d18d8150514ccCRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0x2cfc55af598d18d8150514ccversion num + first 4 bytes overwritten with counter value (0x90010700 here):0100000090010700598d18d8150514cc = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:357f77b267a494c101000000a0030700fb2ce7d1bfd23a0a4db804533e6ffc2301000000880307003736d2b43c149c48same RC4 cipher is used from previous signing operation (i.e., not reset):RC4(0x0102030405060708) = sealed message = 0x357f77b267a494c1trailer buffer gets signature; again uses same RC4 cipher(sequence number is now 1 because of previous signing):RC4(0x00000000c588ca3f01000000) = 0x757b9976fb2ce7d1bfd23a0aversion num + first 4 bytes overwritten w/counter (0xa0030700):01000000a0030700fb2ce7d1bfd23a0a = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0x4db804533e6ffc23trailer buffer signature with sequence 2:RC4(0x00000000c588ca3f02000000) = 0x5eb9ab2f3736d2b43c149c48version num + first 4 bytes overwritten w/counter (0x88030700)01000000880307003736d2b43c149c48 = trailer signature

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key

Demonstration of NTLMv1 authentication with 40-bit Lan Manager Session Key NTLM1 signing and sealing (without key exchange).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4e544c4d5353500001000000b7820000000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb7820000            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000b58281007116b94341ee4e700000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)b5828100            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)7116b94341ee4e70    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c00540000000000000090000000b582800054004500530054004e00540074006500730074004d0045004d0042004500520066271e46d60b246d25fcc3340235841057c2821f490d073304c6e94c5624abad6c922d8e64b6c86d43138f8f0d94fc3f4e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)0000000090000000    Session Key header (empty)b5828000            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")66271e46d60b246d25fcc3340235841057c2821f490d0733    LM/LMv2 Response04c6e94c5624abad6c922d8e64b6c86d43138f8f0d94fc3f    NTLM/NTLMv2 Response--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpperb5828101    flags0000000000000000182e0900182e0900982e0900982e09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000b98a3a22c81e31f99e7eca1e123c04d1    outbound signing keyb98a3a22c81e31f99e7eca1e123c04d1    inbound verifying keyb98a3a22c81e31f99e7eca1e123c04d1    outbound encrypting keyb98a3a22c81e31f99e7eca1e123c04d1    inbound decrypting 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    "TESTNT/test"lmHash = lmEncrypt(password, "KGS!@#$%") = 0x624aac413795cdc1ff17365faf1ffe89trunc(lmHash + pad) = 0x624aac413795cdc1bdbdbdbdbdbdlmResponse[0-7] = 0x66271e46d60b246dLanManagerSessionKey =    lmEncrypt(0x624aac413795cdc1bdbdbdbdbdbd, 0x66271e46d60b246d) =        0xb98a3a22c81e31f99e7eca1e123c04d1Key is weakened to 40-bit w/0xe538b0 = 0xb98a3a22c8e538b0Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000ffffff001a7599e9ad0ad460CRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0xbeb185ce1a7599e9ad0ad460version num + first 4 bytes overwritten with counter value (0xffffff00 here):01000000ffffff001a7599e9ad0ad460 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:075c81a318754894010000006003070033df86be9d65813dda731ecef152bd750100000048030700a61d753437944ee5same RC4 cipher is used from previous signing operation (i.e., not reset):RC4(0x0102030405060708) = sealed message = 0x075c81a318754894trailer buffer gets signature; again uses same RC4 cipher(sequence number is now 1 because of previous signing):RC4(0x00000000c588ca3f01000000) = 0x0004c5b033df86be9d65813dversion num + first 4 bytes overwritten w/counter (0x60030700):010000006003070033df86be9d65813d = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0xda731ecef152bd75trailer buffer signature with sequence 2:RC4(0x00000000c588ca3f02000000) = 0xf012a98ca61d753437944ee5version num + first 4 bytes overwritten w/counter (0x48030700)0100000048030700a61d753437944ee5 = trailer signature

NTLMv1 Datagram-Style Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key With Key Exchange Negotiated

Demonstration of datagram-style authentication with default options (defaults to 40-bit Lan Manager Session Key NTLM1 with key exchange when used with NTLMv1).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with:    ISC_REQ_INTEGRITY | ISC_REQ_CONFIDENTIALITY | ISC_REG_DATAGRAMProduces no token (datagram-style).  Client context can be used for signingand sealing immediately.--------------------------------------------------------------------------------AcceptSecurityContext called with:    ASC_REQ_INTEGRITY | ASC_REQ_CONFIDENTIALITY | ASC_REG_DATAGRAMProduces a Type 2 message:4e544c4d53535000020000000000000030000000f38298e0ada5839570b5cb99000000000000000000000000300000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0000000030000000    Target Name header (empty)f38298e0            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Datagram Style       (0x00000040)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Request Init Response          (0x00100000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)ada5839570b5cb99    Challenge0000000000000000    Context0000000030000000    Target Information header (empty)--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c00540000001000100090000000f582804054004500530054004e00540074006500730074004d0045004d00420045005200e8cff653006525da77c6bef2fed79bc6d7d839f598ead91a4e37300050075eebaa5915480c3620b8ee6fa869cdf16e7c9227ebee8b19a312664fa4ed44bd33774e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)1000100090000000    Session Key header (length 16, offset 144)f5828040            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Datagram Style       (0x00000040)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)    Negotiate Key Exchange         (0x40000000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")e8cff653006525da77c6bef2fed79bc6d7d839f598ead91a    LM/LMv2 Response4e37300050075eebaa5915480c3620b8ee6fa869cdf16e7c    NTLM/NTLMv2 Response9227ebee8b19a312664fa4ed44bd3377                    Session Key--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpperf5828041    flags000000000000000080740a0080740a0000750a0000750a000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000d56070a4c355c2d91693d8f3406d4d82    outbound signing keyd56070a4c355c2d91693d8f3406d4d82    inbound verifying keyd56070a4c355c2d91693d8f3406d4d82    outbound encrypting keyd56070a4c355c2d91693d8f3406d4d82    inbound decrypting 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    "TESTNT/test"lmHash = lmEncrypt(password, "KGS!@#$%") = 0x624aac413795cdc1ff17365faf1ffe89trunc(lmHash + pad) = 0x624aac413795cdc1bdbdbdbdbdbdlmResponse[0-7] = 0xe8cff653006525daLanManagerSessionKey =    lmEncrypt(0x624aac413795cdc1bdbdbdbdbdbd, 0xe8cff653006525da) =        0x97dba8c110cd6b7976c02c203c6be07aKey exchange performed:type3Key (from Type 3) = 0x9227ebee8b19a312664fa4ed44bd3377key = RC4(LanManagerSessionKey, type3Key) =    0xd56070a4c355c2d91693d8f3406d4d82Key is weakened to 40-bit w/0xe538b0 = 0xd56070a4c3e538b0Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:010000009801070012c00705ba25a7ecCRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0x39ec604d12c00705ba25a7ecversion num + first 4 bytes overwritten with counter value (0x98010700 here):010000009801070012c00705ba25a7ec = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:38ee6349d24eca32010000008803070012c00705ba25a7ec38ee6349d24eca32010000007003070012c00705ba25a7ecRC4 cipher is reset after each signing/sealing operation in datagram-style:RC4(key, 0x0102030405060708) = sealed message = 0x38ee6349d24eca32trailer buffer gets signature; RC4 cipher is reset and sequence number is*not* incremented in datagram-style:RC4(key, 0x00000000c588ca3f00000000) = 0x39ec604d12c00705ba25a7ecversion num + first 4 bytes overwritten w/counter (0x88030700):010000008803070012c00705ba25a7ec = trailer signaturesecond message is same:RC4(key, 0x00000000c588ca3f00000000) = 0x39ec604d12c00705ba25a7ecversion num + first 4 bytes overwritten w/counter (0x70030700):010000007003070012c00705ba25a7ec = trailer signature

NTLMv1 Authentication; NTLM1 "Dummy" Signing and Sealing Using the NTLM User Session Key

Demonstration of "dummy" signing and sealing. Context is *not* initialized with support for integrity or confidentiality. "Negotiate Always Sign" is negotiated, which allows the context to be used in dummy signing and sealing.

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with default options.  Produces Type 1 message:4e544c4d5353500001000000078200a0000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 message078200a0            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate 128                  (0x20000000)    Negotiate 56                   (0x80000000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with default options. Produces Type 2 message:4e544c4d53535000020000000c000c0030000000058281a0eacf7d5a2a6fa7d40000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)058281a0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate 56                   (0x80000000)eacf7d5a2a6fa7d4    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)0000000090000000    Session Key header (empty)058280a0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate 56                   (0x80000000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")6c454794b50321a067fdf78e92ee5085a5b0a23057e9125b    LM/LMv2 Responsed2025bc5d6c201af7472550a677ca9904245a16ebb542a8e    NTLM/NTLMv2 Response--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper058281a1    flags000000000000000028f5080028f50800a8f50800a8f508000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000ae33a32dca8c9821844f740d5b3f4d6c    outbound signing keyae33a32dca8c9821844f740d5b3f4d6c    inbound verifying keyae33a32dca8c9821844f740d5b3f4d6c    outbound encrypting keyae33a32dca8c9821844f740d5b3f4d6c    inbound decrypting 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    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93NTLMUserSessionKey = md4(ntlmHash) = 0xae33a32dca8c9821844f740d5b3f4d6cKey is *not* weakened (NTLM1 only weakens Lan Manager Session Keys).Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000000000000000000000000000 ("dummy" signature)--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:2194108dc8f329290100000048020700fa4f9c95a098b2588f88dc2f36cd5e710100000030020700d825f5a1154aa5fcRC4(key, 0x0102030405060708) = sealed message = 0x2194108dc8f32929trailer buffer gets signature; uses same RC4 cipher as sealing(sequence number is 0, previous dummy signing doesn't count):RC4(0x00000000c588ca3f00000000) = 0x039ae5c5fa4f9c95a098b258version num + first 4 bytes overwritten w/counter (0x48020700):0100000048020700fa4f9c95a098b258 = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0x8f88dc2f36cd5e71trailer buffer signature with sequence 1 (previous trailer signatureincremented it):RC4(0x00000000c588ca3f01000000) = 0x6b9317f7d825f5a1154aa5fcversion num + first 4 bytes overwritten w/counter (0x30020700)0100000030020700d825f5a1154aa5fc = trailer signature

NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 128-bit NTLM2 Session Response User Session Key With Key Exchange Negotiated

Demonstration of NTLMv1 authentication with 128-bit NTLM2 Session Response User Session Key NTLM2 signing and sealing, with key exchange enabled.

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.4e544c4d5353500001000000b78208e0000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb78208e0            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000358289e0677f1c557a5ee96c0000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)358289e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)677f1c557a5ee96c    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c00540000001000100090000000358288e054004500530054004e00540074006500730074004d0045004d00420045005200404d1b6f6915258000000000000000000000000000000000ea8cc49f24da157f13436637f77693d8b992d619e584c7ee727a5240822ec7af4e9100c43e6fee7f4e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)1000100090000000    Session Key header (length 16, offset 144)358288e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")404d1b6f6915258000000000000000000000000000000000    LM/LMv2 Responseea8cc49f24da157f13436637f77693d8b992d619e584c7ee    NTLM/NTLMv2 Response727a5240822ec7af4e9100c43e6fee7f                    Session Key--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:48a42e7848a42e780000000000000000000000000000000070f10b00    server context handle dwUpper358289e1    flags0000000000000000382e09003c2e0900b82e0900c82f09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f200100006c713b60e6571035c9396ece1e456395    outbound signing keye775c02a63d159ec64185f6d7d993344    inbound verifying keye9b0f8e2cbf7b453b8389e8d2d7bb4ba    outbound encrypting keycc0fc51f360b7da837cde6cb417fd735    inbound decrypting 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    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93NTLMUserSessionKey = md4(ntlmHash) = 0xae33a32dca8c9821844f740d5b3f4d6cchallenge (from Type 2) = 0x677f1c557a5ee96cnonce (from Type 3) = 0x404d1b6f69152580NTLM2SessionResponseUserSessionKey =    HMAC(NTLMUserSessionKey, challenge + nonce) =        0x0d4b30a8750b73ab2dab39e889455fcdKey exchange performed:type3Key (from Type 3) = 0x727a5240822ec7af4e9100c43e6fee7fkey = RC4(NTLM2SessionResponseUserSessionKey, type3Key) =    0x5764dc0a93b1292fa898c29524c30a54We are using server context:serverSigningConstant =    "session key to server-to-client signing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207369676e696e67206b6579206d6167696320636f6e7374616e7400serverSealingConstant =    "session key to server-to-client sealing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207365616c696e67206b6579206d6167696320636f6e7374616e7400signingKey = MD5(key + serverSigningConstant) =    0x6c713b60e6571035c9396ece1e456395User Session Key is not weakened (128-bit negotiated).sealingKey = MD5(key + serverSealingConstant) =    0xe9b0f8e2cbf7b453b8389e8d2d7bb4baCalled MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:0100000069de1aff9cbee43100000000Sequence number is 0.seqnum + message = 0x000000000102030405060708HMAC(signingKey, 0x000000000102030405060708) =    0x9d642651faec52f2164297dcaaa1ff6esig = RC4(sealingKey, first 8 bytes) = 0x69de1aff9cbee431version num + sig + seqnum:0100000069de1aff9cbee43100000000 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:5b4cbbd3b2d8e8a401000000272c6dee5b236fe20100000029535954c1e00fb9010000002922b8fcada4cda202000000Uses RC4 cipher from previous signing operation (key exchange encryptssignature with sealing key as well).RC4(0x0102030405060708) = sealed message = 0x5b4cbbd3b2d8e8a4trailer buffer gets signature (sequence number is now 1 because of previoussigning, same RC4 cipher used for this signature too):HMAC(signingKey, 0x010000000102030405060708) =    0x1b7fc502e4cc73b6d85360d7ee052800sig = RC4(first 8 bytes) = 0x272c6dee5b236fe2version num + sig + seqnum:01000000272c6dee5b236fe201000000 = trailer signaturesecond message is same, using RC4 cipher from previous operations:RC4(0x0102030405060708) = sealed message = 0x29535954c1e00fb9trailer buffer signature with sequence 2:HMAC(signingKey, 0x020000000102030405060708) =   0x3e46a45716671a6e0d056636f77db4bbsig = RC4(first 8 bytes) = 0x2922b8fcada4cda2version num + sig + seqnum:010000002922b8fcada4cda202000000 = trailer signature

NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 40-bit NTLM2 Session Response User Session Key

Demonstration of NTLMv1 authentication with 40-bit NTLM2 Session Response User Session Key NTLM2 signing and sealing (without key exchange).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4e544c4d5353500001000000b7820800000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb7820800            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)0000000000000000    Supplied Domain (empty, supplied credentials)0000000000000000    Supplied Workstation (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c003000000035828900919013ccde5c4d160000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35828900            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)919013ccde5c4d16    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c005400000000000000900000003582880054004500530054004e00540074006500730074004d0045004d0042004500520002a668799b43b02600000000000000000000000000000000191c91d68a26a93382ec89178c1e496d8f2f63a1c7dc0b544e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)0000000090000000    Session Key header (empty)35828800            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")02a668799b43b02600000000000000000000000000000000    LM/LMv2 Response191c91d68a26a93382ec89178c1e496d8f2f63a1c7dc0b54    NTLM/NTLMv2 Response--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35828901    flags0000000000000000f8290900fc290900782a0900882b09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000605b738984f36aea7d2ccc5678670f2c    outbound signing key94d75dd6591eb8569d8480b5c9c25136    inbound verifying keye4c55ca209611e9e007009731b7103d5    outbound encrypting key738e75e9b0df0ac9139839abf5cc8354    inbound decrypting key00000000000000000000000037aa90adbac5442beb5c77f553b782d01859687c2e421e524e2fbc4ad5ff055543657a283af2366b3f3cafa80372a3a781b123dd6f2c22e45e0c57d23bd78399f64935c94bbf9112156a67a2dc843e1a7069f8ec30f99388fa61c4cf4c3d3824b046df9c31fc0a0150d6638ca17fb651c79db25d07efbea5dea02580fe406211ea9b1341b41f76e366857d5afbe92adb6ee2940bfd6c4fe12995b5acc05fbb73a98bbd33b906ae14a4da00cb0dcc1b75f0edc2792d9e60cef1c192741d8a10398d7b479a97b30e20f4217ef39fe6c30948199604c8f79856d1ee4dd9e589648e26ca86c67802e78f5b34e8a617d3ab5408582745cdd416711c32e06d87b80fd800000000000000000000000000000000eb024b64187446dcf798db69a299356807ba78fec2b642e6cd77a097a80bb9a538e7548a935d923dbd22e1b7d80127fc1cc9fad61e404eac033f6bab10e57923878f729e84500ce97139d5cb8c11c7b21741e2325f56a34aad757a804f34ed19a747bf05af9b912f94ffea700dd43a8806d73eb4458bd97e1a375c6d9633f3c649092dc8635a9a589ce35221c5dda1f926ef1f6a5bc03bb1ce65e089149d2baa28b3cab59f448655306c25133629bc812c57be592a1b0e1204537bcf00d176b03c0faecce8f6c4dfd0674cfbd27d95fdf1da318e8d8582bbec7f16f0c162eea60a8324f26660151d2eb851736edea9e4f86f08a45e4dc3d37c48f54390f46120000000000000000054004500530054004e0054005c007400650073007400    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93NTLMUserSessionKey = md4(ntlmHash) = 0xae33a32dca8c9821844f740d5b3f4d6cchallenge (from Type 2) = 0x919013ccde5c4d16nonce (from Type 3) = 0x02a668799b43b026NTLM2SessionResponseUserSessionKey =    HMAC(NTLMUserSessionKey, challenge + nonce) =        0x6b60097a8f9dbbff2d23f5b15377ca28We are using server context:serverSigningConstant =    "session key to server-to-client signing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207369676e696e67206b6579206d6167696320636f6e7374616e7400serverSealingConstant =    "session key to server-to-client sealing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207365616c696e67206b6579206d6167696320636f6e7374616e7400signingKey = MD5(key + serverSigningConstant) =    0x605b738984f36aea7d2ccc5678670f2cUser Session Key is weakened to 40-bit for sealing by truncating =    0x6b60097a8fsealingKey = MD5(weakenedKey + serverSealingConstant) =    0xe4c55ca209611e9e007009731b7103d5Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000d1e2d811145d81ec00000000Sequence number is 0.seqnum + message = 0x000000000102030405060708HMAC(signingKey, 0x000000000102030405060708) =    0xd1e2d811145d81ecf5f8723312c75e3cversion num + first 8 bytes + seqnum:01000000d1e2d811145d81ec00000000 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:ab8d38bb0cad7dd601000000eed64de8afb80c8001000000b011cc07a7f6127b01000000644a8509d73ac48c02000000RC4(sealingKey, 0x0102030405060708) = sealed message = 0xab8d38bb0cad7dd6trailer buffer gets signature (sequence number is now 1 because of previoussigning):HMAC(signingKey, 0x010000000102030405060708) =    0xeed64de8afb80c801ea5ddd1d98cbdc8version num + first 8 bytes + seqnum:01000000eed64de8afb80c8001000000 = trailer signaturesecond message is same, using RC4 cipher from previous sealing operation:RC4(0x0102030405060708) = sealed message = 0xb011cc07a7f6127btrailer buffer signature with sequence 2:HMAC(signingKey, 0x020000000102030405060708) =    0x644a8509d73ac48c8f5a7f7f65bc8381version num + first 8 bytes + seqnum:01000000644a8509d73ac48c02000000 = trailer signature

NTLMv2 Authentication; NTLM1 Signing and Sealing Using the 40-bit NTLMv2 User Session Key

Demonstration of NTLMv2 authentication with NTLMv2 User Session Key NTLM1 signing and sealing (without key exchange).

LMCompatibilityLevel set to 3 (LMv2/NTLMv2).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4e544c4d535350000100000037820000000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 message37820000            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000358281000033b02d17275b770000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35828100            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)0033b02d17275b77    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000076007600780000000c000c0040000000080008004c0000000c000c005400000000000000ee0000003582800054004500530054004e00540074006500730074004d0045004d004200450052005d55a02b60a40526ac9a1e4d15fa45a0f2e6329726c598e8f77c67dad00b93216242b197fe6addfa0101000000000000502db638677bc301f2e6329726c598e80000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d0000000000000000004e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)7600760078000000    NTLM/NTLMv2 Response header (length 118, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)00000000ee000000    Session Key header (empty)35828000            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")5d55a02b60a40526ac9a1e4d15fa45a0f2e6329726c598e8    LM/LMv2 ResponseNTLM/NTLMv2 Response:f77c67dad00b93216242b197fe6addfa0101000000000000502db638677bc301f2e6329726c598e80000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d000000000000000000--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35828101    flags, also has an unknown flag set0000000000000000782e0900782e0900f82e0900f82e09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f200100001c4c7aaa7403acf01b1fa565bc950810    outbound signing key1c4c7aaa7403acf01b1fa565bc950810    inbound verifying key1c4c7aaa7403acf01b1fa565bc950810    outbound encrypting key1c4c7aaa7403acf01b1fa565bc950810    inbound decrypting 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    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93ntlmv2Hash = hmac(ntlmHash, "TESTTESTNT") = 0xc4ea95cb148df11bf9d7c3611ad6d722challenge (from Type 2) = 0x0033b02d17275b77blob (from Type 3) = 0x0101000000000000502db638677bc301f2e6329726c598e80000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d000000000000000000NTLMv2UserSessionKey = HMAC(ntlmv2Hash(HMAC(ntlmv2Hash, challenge + blob))) =    0x1c4c7aaa7403acf01b1fa565bc950810Key is *not* weakened (NTLM1 only weakens Lan Manager Session Keys).Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000ffffff0051cefea77f098ee3CRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0x8661cb7d51cefea77f098ee3version num + first 4 bytes overwritten with counter value (0xffffff00 here):01000000ffffff0051cefea77f098ee3 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:f483b904264d83060100000098010700bd9719c0b34f5362022cc2127f9e206e01000000800307001855ec8494231273same RC4 cipher is used from previous signing operation (i.e., not reset):RC4(0x0102030405060708) = sealed message = 0xf483b904264d8306trailer buffer gets signature; again uses same RC4 cipher(sequence number is now 1 because of previous signing):RC4(0x00000000c588ca3f01000000) = 0x2246e9cbbd9719c0b34f5362version num + first 4 bytes overwritten w/counter (0x98010700):0100000098010700bd9719c0b34f5362 = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0x022cc2127f9e206etrailer buffer signature with sequence 2:RC4(0x00000000c588ca3f02000000) = 0x6fde4d031855ec8494231273version num + first 4 bytes overwritten w/counter (0x80030700)01000000800307001855ec8494231273 = trailer signature

NTLMv2 Authentication; NTLM2 Signing and Sealing Using the 56-bit NTLMv2 User Session Key

Demonstration of NTLMv2 authentication with 56-bit NTLMv2 User Session Key NTLM2 signing and sealing (without key exchange).

LMCompatibilityLevel set to 3 (LMv2/NTLMv2).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)4e544c4d5353500001000000b7820880000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb7820880            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 56                   (0x80000000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c003000000035828980514246973ea892c10000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35828980            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 56                   (0x80000000)514246973ea892c1    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000076007600780000000c000c0040000000080008004c0000000c000c005400000000000000ee0000003582888054004500530054004e00540074006500730074004d0045004d00420045005200bf2e015119f6bdb3f6fdb768aa12d478f5ce3d2401c8f6e9caa4da8f25d5e840974ed8976d3ada46010100000000000030fa7e3c677bc301f5ce3d2401c8f6e90000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d0000000000000000004e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)7600760078000000    NTLM/NTLMv2 Response header (length 118, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)00000000ee000000    Session Key header (empty)35828880            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 56                   (0x80000000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")bf2e015119f6bdb3f6fdb768aa12d478f5ce3d2401c8f6e9    LM/LMv2 ResponseNTLM/NTLMv2 Response:caa4da8f25d5e840974ed8976d3ada46010100000000000030fa7e3c677bc301f5ce3d2401c8f6e90000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d000000000000000000--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35828981    flags0000000000000000282e09002c2e0900a82e0900b82f09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000f7301e5d23f1d578c51ec0728b67453e    outbound signing key06403212f9e8c05ce1739938c200eca5    inbound verifying key3d6483dce52cd6c4d7553545e607d92d    outbound encrypting keyccc6efbcea980c0ac685753a4c9bbe0c    inbound decrypting 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    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93ntlmv2Hash = hmac(ntlmHash, "TESTTESTNT") = 0xc4ea95cb148df11bf9d7c3611ad6d722challenge (from Type 2) = 0x514246973ea892c1blob (from Type 3) = 0x010100000000000030fa7e3c677bc301f5ce3d2401c8f6e90000000002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d000000000000000000NTLMv2UserSessionKey = HMAC(ntlmv2Hash(HMAC(ntlmv2Hash, challenge + blob))) =    0x62ff13231f566f5dadf7391e183b5f39We are using server context:serverSigningConstant =    "session key to server-to-client signing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207369676e696e67206b6579206d6167696320636f6e7374616e7400serverSealingConstant =    "session key to server-to-client sealing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207365616c696e67206b6579206d6167696320636f6e7374616e7400signingKey = MD5(key + serverSigningConstant) =    0xf7301e5d23f1d578c51ec0728b67453eUser Session Key is weakened to 56-bit for sealing by truncating =    0x62ff13231f566fsealingKey = MD5(weakenedKey + serverSealingConstant) =    0x3d6483dce52cd6c4d7553545e607d92dCalled MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000fa317a333d8f510c00000000Sequence number is 0.seqnum + message = 0x000000000102030405060708HMAC(signingKey, 0x000000000102030405060708) =    0xfa317a333d8f510cccab257d9f2193c4version num + first 8 bytes + seqnum:01000000fa317a333d8f510c00000000 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:a8e6671c79cf265701000000673773407fb60b42010000002fe89f6c6ea06d4b01000000244e0bcbce6ec16c02000000RC4(sealingKey, 0x0102030405060708) = sealed message = 0xa8e6671c79cf2657trailer buffer gets signature (sequence number is now 1 because of previoussigning):HMAC(signingKey, 0x010000000102030405060708) =    0x673773407fb60b428f70358ca67720baversion num + first 8 bytes + seqnum:01000000673773407fb60b4201000000 = trailer signaturesecond message is same, using RC4 cipher from previous sealing operation:RC4(0x0102030405060708) = sealed message = 0x2fe89f6c6ea06d4btrailer buffer signature with sequence 2:HMAC(signingKey, 0x020000000102030405060708) =    0x244e0bcbce6ec16ce3493f55854bcc5cversion num + first 8 bytes + seqnum:01000000244e0bcbce6ec16c02000000 = trailer signature

Anonymous NTLMv1 Authentication; NTLM2 Signing and Sealing Using the 128-bit Null User Session Key With Key Exchange Negotiated

Demonstration of anonymous authentication with signing and sealing.

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with empty string ("") for domain, user, andpassword.--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Produces Type 1 message:4e544c4d5353500001000000b78208e0000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb78208e0            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c0030000000358289e05bce6f12f47ddbdf0000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)358289e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)5bce6f12f47ddbdf    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000010001004c000000000000004d000000000000004000000000000000400000000c000c0040000000100010004d000000358a88e04d0045004d0042004500520000c1442e6cca8c010e77138430aa35738e4e544c4d53535000    "NTLMSSP"03000000            Type 3 message010001004c000000    LM/LMv2 Response header (length 1, offset 76)000000004d000000    NTLM/NTLMv2 Response header (empty)0000000040000000    Domain Name header (empty)0000000040000000    User Name header (empty)0c000c0040000000    Workstation Name header (length 12, offset 64)100010004d000000    Session Key header (length 16, offset 77)358a88e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Anonymous            (0x00000800)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4d0045004d00420045005200            Workstation Name ("MEMBER")00                                  LM/LMv2 Responsec1442e6cca8c010e77138430aa35738e    Session Key--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export (on Win2k, appears to vary by OS):40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper358a89e1    flags0000000000000000e8290900ec290900682a0900782b090000000000000000000000000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f000000009128c3e5df618a48a83b44cfd92d58fe    outbound signing key594757aaa803afd943de25e087e3f9f1    inbound verifying keyfc52e8bf1605ab57e89c6d6b4ffa92f6    outbound encrypting key96465577ba181d141711572e5e15fe5d    inbound decrypting 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 User Session Key = 0x00000000000000000000000000000000Key exchange performed:type3Key (from Type 3) = 0xc1442e6cca8c010e77138430aa35738ekey = RC4(AnonymousUserSessionKey, type3Key) =    0x1f5ca72d69bb5c34fd159a57fd5be1e3We are using server context:serverSigningConstant =    "session key to server-to-client signing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74207369676e696e67206b6579206d6167696320636f6e7374616e7400serverSealingConstant =    "session key to server-to-client sealing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74207365616c696e67206b6579206d6167696320636f6e7374616e7400signingKey = MD5(key + serverSigningConstant) =    0x9128c3e5df618a48a83b44cfd92d58fesealingKey = MD5(key + serverSealingConstant) =    0xfc52e8bf1605ab57e89c6d6b4ffa92f6Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000ae0cbe0dd0b2110300000000Sequence number is 0.seqnum + message = 0x000000000102030405060708HMAC(signingKey, 0x000000000102030405060708) =    0xc14074817421530195b4532d61a4e625sig = RC4(sealingKey, first 8 bytes) = 0xae0cbe0dd0b21103version num + sig + seqnum:01000000ae0cbe0dd0b2110300000000 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:fb2e1d6ff8a3569a01000000cc2c5bf59319e7ca010000001e2216588e5a7d9801000000e9a3066b8fab0bf102000000Uses RC4 cipher from previous signing operation (key exchange encryptssignature with sealing key as well).RC4(0x0102030405060708) = sealed message = 0xfb2e1d6ff8a3569atrailer buffer gets signature (sequence number is now 1 because of previoussigning, same RC4 cipher used for this signature too):HMAC(signingKey, 0x010000000102030405060708) =    0x25141e76f441b10622cfaf0e61450663sig = RC4(first 8 bytes) = 0xcc2c5bf59319e7caversion num + sig + seqnum:01000000cc2c5bf59319e7ca01000000 = trailer signaturesecond message is same, using RC4 cipher from previous operations:RC4(0x0102030405060708) = sealed message = 0x1e2216588e5a7d98trailer buffer signature with sequence 2:HMAC(signingKey, 0x020000000102030405060708) =   0x7efa2ba18ed911696a0f4d571b05a244sig = RC4(first 8 bytes) = 0xe9a3066b8fab0bf1version num + sig + seqnum:01000000e9a3066b8fab0bf102000000 = trailer signature

Local NTLMv1 Authentication; NTLM2 Signing and Sealing Using an Unknown Session Key With Key Exchange Negotiated (Analysis Incomplete)

Demonstration of local authentication with signing and sealing. It is assumed that the User Session Key derivation and Key Exchange processes are performed normally offline within the established local context (in the absence of the required information being provided over-the-wire).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with NULL identity (using default credentialshandle for authenticated local user).--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Produces Type 1 message:4e544c4d5353500001000000b7b208e0060006002600000006000600200000004d454d424552544553544e544e544c4d53535000    "NTLMSSP"01000000            Type 1 messageb7b208e0            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM                 (0x00000200)    Negotiate Domain Supplied      (0x00001000)    Negotiate Workstation Supplied (0x00002000)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)0600060026000000    Supplied Domain header (length 6, offset 38)0600060020000000    Supplied Workstation header (length 6, offset 32)4d454d424552    Supplied Workstation ("MEMBER")544553544e54    Supplied Domain ("TESTNT")--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c003000000035c289e0d7ef496afa05535208ee0b0000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35c289e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Local Call           (0x00004000)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)d7ef496afa055352    Challenge08ee0b0000000000    Context (equal to server context handle's dwUpper field)460046003c000000    Target Information header (length 70, offset 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d535350000300000000000000400000000000000040000000000000004000000000000000400000000000000040000000000000004000000035c288e04e544c4d53535000    "NTLMSSP"03000000            Type 3 message0000000040000000    LM/LMv2 Response header (empty, local authentication)0000000040000000    NTLM/NTLMv2 Response header (empty, local authentication)0000000040000000    Domain Name header (empty, local authentication)0000000040000000    User Name header (empty, local authentication)0000000040000000    Workstation Name header (empty, local authentication)0000000040000000    Session Key header (empty)35c288e0            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Local Call           (0x00004000)    Negotiate Always Sign          (0x00008000)    Negotiate NTLM2 Key            (0x00080000)    Negotiate Target Info          (0x00800000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35c289e1    flags0000000000000000182e09001c2e0900982e0900a82f09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f0000000065836771d7bf52df502634e521b3154b    outbound signing key9ed7ce6558f0f26db1fbf5163d7b24f9    inbound verifying keyf56d6b81749b7adaf3467f37bc36224e    outbound encrypting key65adf5ede40e84e7338d681e6cbc38ff    inbound decrypting 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    "TESTNT/test"User Session Key = ????Key exchange performed somehow?  Shows up in signatures.We are using server context:serverSigningConstant =    "session key to server-to-client signing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207369676e696e67206b6579206d6167696320636f6e7374616e7400serverSealingConstant =    "session key to server-to-client sealing key magic constant" =        0x73657373696f6e206b657920746f207365727665722d746f2d636c69656e74        207365616c696e67206b6579206d6167696320636f6e7374616e7400signingKey = MD5(key + serverSigningConstant) =    0x65836771d7bf52df502634e521b3154b (from context export)sealingKey = MD5(key + serverSealingConstant) =    0xf56d6b81749b7adaf3467f37bc36224e (from context export)Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:01000000adc70c8bd4834ae800000000Sequence number is 0.seqnum + message = 0x000000000102030405060708HMAC(signingKey, 0x000000000102030405060708) =    0xb0bd637382da53f4ad3edf2c5a2c9592sig = RC4(sealingKey, first 8 bytes) = 0xadc70c8bd4834ae8version num + sig + seqnum:01000000adc70c8bd4834ae800000000 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:9c89720008251ab601000000d4af70567f5ab1df01000000a8950e40b10e9af501000000c5447ccf7102d98c02000000Uses RC4 cipher from previous signing operation (key exchange encryptssignature with sealing key as well).RC4(0x0102030405060708) = sealed message = 0x9c89720008251ab6trailer buffer gets signature (sequence number is now 1 because of previoussigning, same RC4 cipher used for this signature too):HMAC(signingKey, 0x010000000102030405060708) =    0xcd1d04a1962b7d82e6ffd7c37871bf15sig = RC4(first 8 bytes) = 0xd4af70567f5ab1dfversion num + sig + seqnum:01000000d4af70567f5ab1df01000000 = trailer signaturesecond message is same, using RC4 cipher from previous operations:RC4(0x0102030405060708) = sealed message = 0xa8950e40b10e9af5trailer buffer signature with sequence 2:HMAC(signingKey, 0x020000000102030405060708) =   0x3011549106db10de5694f567749cb9ebsig = RC4(first 8 bytes) = 0xc5447ccf7102d98cversion num + sig + seqnum:01000000c5447ccf7102d98c02000000 = trailer signature

Appendix D: Java Implementation of the Type 3 Response Calculations

Listed below is an annotated sample implementation of the various Type 3 response calculations in Java. This example requires a JCE provider implementing the MD4 message-digest algorithm; the author recommends GNU Crypto, available at

http://www.gnu.org/software/gnu-crypto/.

import java.security.Key;import java.security.MessageDigest;import javax.crypto.Cipher;import javax.crypto.spec.SecretKeySpec;/** * Calculates the various Type 3 responses. */public class Responses {    /**     * Calculates the LM Response for the given challenge, using the specified     * password.     *     * @param password The user's password.     * @param challenge The Type 2 challenge from the server.     *     * @return The LM Response.     */    public static byte[] getLMResponse(String password, byte[] challenge)            throws Exception {        byte[] lmHash = lmHash(password);        return lmResponse(lmHash, challenge);    }    /**     * Calculates the NTLM Response for the given challenge, using the     * specified password.     *     * @param password The user's password.     * @param challenge The Type 2 challenge from the server.     *     * @return The NTLM Response.     */    public static byte[] getNTLMResponse(String password, byte[] challenge)            throws Exception {        byte[] ntlmHash = ntlmHash(password);        return lmResponse(ntlmHash, challenge);    }    /**     * Calculates the NTLMv2 Response for the given challenge, using the     * specified authentication target, username, password, target information     * block, and client nonce.     *     * @param target The authentication target (i.e., domain).     * @param user The username.      * @param password The user's password.     * @param targetInformation The target information block from the Type 2     * message.     * @param challenge The Type 2 challenge from the server.     * @param clientNonce The random 8-byte client nonce.      *     * @return The NTLMv2 Response.     */    public static byte[] getNTLMv2Response(String target, String user,            String password, byte[] targetInformation, byte[] challenge,                    byte[] clientNonce) throws Exception {        byte[] ntlmv2Hash = ntlmv2Hash(target, user, password);        byte[] blob = createBlob(targetInformation, clientNonce);        return lmv2Response(ntlmv2Hash, blob, challenge);    }    /**     * Calculates the LMv2 Response for the given challenge, using the     * specified authentication target, username, password, and client     * challenge.     *     * @param target The authentication target (i.e., domain).     * @param user The username.     * @param password The user's password.     * @param challenge The Type 2 challenge from the server.     * @param clientNonce The random 8-byte client nonce.     *     * @return The LMv2 Response.      */    public static byte[] getLMv2Response(String target, String user,            String password, byte[] challenge, byte[] clientNonce)                    throws Exception {        byte[] ntlmv2Hash = ntlmv2Hash(target, user, password);        return lmv2Response(ntlmv2Hash, clientNonce, challenge);    }    /**     * Calculates the NTLM2 Session Response for the given challenge, using the     * specified password and client nonce.     *     * @param password The user's password.     * @param challenge The Type 2 challenge from the server.     * @param clientNonce The random 8-byte client nonce.     *     * @return The NTLM2 Session Response.  This is placed in the NTLM     * response field of the Type 3 message; the LM response field contains     * the client nonce, null-padded to 24 bytes.     */    public static byte[] getNTLM2SessionResponse(String password,            byte[] challenge, byte[] clientNonce) throws Exception {        byte[] ntlmHash = ntlmHash(password);        MessageDigest md5 = MessageDigest.getInstance("MD5");        md5.update(challenge);        md5.update(clientNonce);        byte[] sessionHash = new byte[8];        System.arraycopy(md5.digest(), 0, sessionHash, 0, 8);        return lmResponse(ntlmHash, sessionHash);    }    /**     * Creates the LM Hash of the user's password.     *     * @param password The password.     *     * @return The LM Hash of the given password, used in the calculation     * of the LM Response.     */    private static byte[] lmHash(String password) throws Exception {        byte[] oemPassword = password.toUpperCase().getBytes("US-ASCII");        int length = Math.min(oemPassword.length, 14);        byte[] keyBytes = new byte[14];        System.arraycopy(oemPassword, 0, keyBytes, 0, length);        Key lowKey = createDESKey(keyBytes, 0);        Key highKey = createDESKey(keyBytes, 7);        byte[] magicConstant = "KGS!@#$%".getBytes("US-ASCII");        Cipher des = Cipher.getInstance("DES/ECB/NoPadding");        des.init(Cipher.ENCRYPT_MODE, lowKey);        byte[] lowHash = des.doFinal(magicConstant);        des.init(Cipher.ENCRYPT_MODE, highKey);        byte[] highHash = des.doFinal(magicConstant);        byte[] lmHash = new byte[16];        System.arraycopy(lowHash, 0, lmHash, 0, 8);        System.arraycopy(highHash, 0, lmHash, 8, 8);        return lmHash;    }    /**     * Creates the NTLM Hash of the user's password.     *     * @param password The password.     *     * @return The NTLM Hash of the given password, used in the calculation     * of the NTLM Response and the NTLMv2 and LMv2 Hashes.     */    private static byte[] ntlmHash(String password) throws Exception {        byte[] unicodePassword = password.getBytes("UnicodeLittleUnmarked");        MessageDigest md4 = MessageDigest.getInstance("MD4");        return md4.digest(unicodePassword);    }    /**     * Creates the NTLMv2 Hash of the user's password.     *     * @param target The authentication target (i.e., domain).     * @param user The username.     * @param password The password.     *     * @return The NTLMv2 Hash, used in the calculation of the NTLMv2     * and LMv2 Responses.      */    private static byte[] ntlmv2Hash(String target, String user,            String password) throws Exception {        byte[] ntlmHash = ntlmHash(password);        String identity = user.toUpperCase() + target;        return hmacMD5(identity.getBytes("UnicodeLittleUnmarked"), ntlmHash);    }    /**     * Creates the LM Response from the given hash and Type 2 challenge.     *     * @param hash The LM or NTLM Hash.     * @param challenge The server challenge from the Type 2 message.     *     * @return The response (either LM or NTLM, depending on the provided     * hash).     */    private static byte[] lmResponse(byte[] hash, byte[] challenge)            throws Exception {        byte[] keyBytes = new byte[21];        System.arraycopy(hash, 0, keyBytes, 0, 16);        Key lowKey = createDESKey(keyBytes, 0);        Key middleKey = createDESKey(keyBytes, 7);        Key highKey = createDESKey(keyBytes, 14);        Cipher des = Cipher.getInstance("DES/ECB/NoPadding");        des.init(Cipher.ENCRYPT_MODE, lowKey);        byte[] lowResponse = des.doFinal(challenge);        des.init(Cipher.ENCRYPT_MODE, middleKey);        byte[] middleResponse = des.doFinal(challenge);        des.init(Cipher.ENCRYPT_MODE, highKey);        byte[] highResponse = des.doFinal(challenge);        byte[] lmResponse = new byte[24];        System.arraycopy(lowResponse, 0, lmResponse, 0, 8);        System.arraycopy(middleResponse, 0, lmResponse, 8, 8);        System.arraycopy(highResponse, 0, lmResponse, 16, 8);        return lmResponse;    }    /**     * Creates the LMv2 Response from the given hash, client data, and     * Type 2 challenge.     *     * @param hash The NTLMv2 Hash.     * @param clientData The client data (blob or client nonce).     * @param challenge The server challenge from the Type 2 message.     *     * @return The response (either NTLMv2 or LMv2, depending on the     * client data).     */    private static byte[] lmv2Response(byte[] hash, byte[] clientData,            byte[] challenge) throws Exception {        byte[] data = new byte[challenge.length + clientData.length];        System.arraycopy(challenge, 0, data, 0, challenge.length);        System.arraycopy(clientData, 0, data, challenge.length,                         clientData.length);        byte[] mac = hmacMD5(data, hash);        byte[] lmv2Response = new byte[mac.length + clientData.length];        System.arraycopy(mac, 0, lmv2Response, 0, mac.length);        System.arraycopy(clientData, 0, lmv2Response, mac.length,                         clientData.length);        return lmv2Response;    }    /**     * Creates the NTLMv2 blob from the given target information block and     * client nonce.     *     * @param targetInformation The target information block from the Type 2     * message.     * @param clientNonce The random 8-byte client nonce.     *     * @return The blob, used in the calculation of the NTLMv2 Response.     */    private static byte[] createBlob(byte[] targetInformation,            byte[] clientNonce) {        byte[] blobSignature = new byte[] {            (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00        };        byte[] reserved = new byte[] {            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00        };        byte[] unknown1 = new byte[] {            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00        };        byte[] unknown2 = new byte[] {            (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00        };        long time = System.currentTimeMillis();        time += 11644473600000l; // milliseconds from January 1, 1601 -> epoch.        time *= 10000; // tenths of a microsecond.        // convert to little-endian byte array.        byte[] timestamp = new byte[8];        for (int i = 0; i < 8; i++) {            timestamp[i] = (byte) time;            time >>>= 8;        }        byte[] blob = new byte[blobSignature.length + reserved.length +                               timestamp.length + clientNonce.length +                               unknown1.length + targetInformation.length +                               unknown2.length];        int offset = 0;        System.arraycopy(blobSignature, 0, blob, offset, blobSignature.length);        offset += blobSignature.length;        System.arraycopy(reserved, 0, blob, offset, reserved.length);        offset += reserved.length;        System.arraycopy(timestamp, 0, blob, offset, timestamp.length);        offset += timestamp.length;        System.arraycopy(clientNonce, 0, blob, offset,                         clientNonce.length);        offset += clientNonce.length;        System.arraycopy(unknown1, 0, blob, offset, unknown1.length);        offset += unknown1.length;        System.arraycopy(targetInformation, 0, blob, offset,                         targetInformation.length);        offset += targetInformation.length;        System.arraycopy(unknown2, 0, blob, offset, unknown2.length);        return blob;    }    /**     * Calculates the HMAC-MD5 hash of the given data using the specified     * hashing key.     *     * @param data The data for which the hash will be calculated.      * @param key The hashing key.     *     * @return The HMAC-MD5 hash of the given data.     */    private static byte[] hmacMD5(byte[] data, byte[] key) throws Exception {        byte[] ipad = new byte[64];        byte[] opad = new byte[64];        for (int i = 0; i < 64; i++) {            ipad[i] = (byte) 0x36;            opad[i] = (byte) 0x5c;        }        for (int i = key.length - 1; i >= 0; i--) {            ipad[i] ^= key[i];            opad[i] ^= key[i];        }        byte[] content = new byte[data.length + 64];        System.arraycopy(ipad, 0, content, 0, 64);        System.arraycopy(data, 0, content, 64, data.length);        MessageDigest md5 = MessageDigest.getInstance("MD5");        data = md5.digest(content);        content = new byte[data.length + 64];        System.arraycopy(opad, 0, content, 0, 64);        System.arraycopy(data, 0, content, 64, data.length);        return md5.digest(content);    }    /**     * Creates a DES encryption key from the given key material.     *     * @param bytes A byte array containing the DES key material.     * @param offset The offset in the given byte array at which     * the 7-byte key material starts.     *     * @return A DES encryption key created from the key material     * starting at the specified offset in the given byte array.     */    private static Key createDESKey(byte[] bytes, int offset) {        byte[] keyBytes = new byte[7];        System.arraycopy(bytes, offset, keyBytes, 0, 7);        byte[] material = new byte[8];        material[0] = keyBytes[0];        material[1] = (byte) (keyBytes[0] << 7 | (keyBytes[1] & 0xff) >>> 1);        material[2] = (byte) (keyBytes[1] << 6 | (keyBytes[2] & 0xff) >>> 2);        material[3] = (byte) (keyBytes[2] << 5 | (keyBytes[3] & 0xff) >>> 3);        material[4] = (byte) (keyBytes[3] << 4 | (keyBytes[4] & 0xff) >>> 4);        material[5] = (byte) (keyBytes[4] << 3 | (keyBytes[5] & 0xff) >>> 5);        material[6] = (byte) (keyBytes[5] << 2 | (keyBytes[6] & 0xff) >>> 6);        material[7] = (byte) (keyBytes[6] << 1);        oddParity(material);        return new SecretKeySpec(material, "DES");    }    /**     * Applies odd parity to the given byte array.     *     * @param bytes The data whose parity bits are to be adjusted for     * odd parity.     */    private static void oddParity(byte[] bytes) {        for (int i = 0; i < bytes.length; i++) {            byte b = bytes[i];            boolean needsParity = (((b >>> 7) ^ (b >>> 6) ^ (b >>> 5) ^                                    (b >>> 4) ^ (b >>> 3) ^ (b >>> 2) ^                                    (b >>> 1)) & 0x01) == 0;            if (needsParity) {                bytes[i] |= (byte) 0x01;            } else {                bytes[i] &= (byte) 0xfe;            }        }    }}

Appendix C: Sample NTLMSSP Operation Decompositions

This section contains detailed analysis and decomposition of various authentication and signing/sealing operations. This is by no means a comprehensive catalog of possible scenarios, but does include some of the more interesting variants. These were produced by calling the InitializeSecurityContext and AcceptSecurityContext SSPI functions between two peers, and applying subtle manipulations to the resulting NTLM messages. After the context was established, the ExportSecurityContext function was called to dump the contents of the context to a file, for use in subsequent offline analysis. Additionally, the MakeSignature and EncryptMessage functions were used to perform signing and sealing, respectively.

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the NTLM User Session Key

Demonstration of NTLMv1 authentication with NTLM User Session Key NTLM1 signing and sealing (without key exchange).

LMCompatibilityLevel set to 0 (LM/NTLM).AcquireCredentialsHandle called with domain "TESTNT", user "test", password"test1234".--------------------------------------------------------------------------------InitializeSecurityContext called with ISC_REQ_INTEGRITY andISC_REQ_CONFIDENTIALITY.  Following flags were masked off of resulting Type 1message:    Negotiate Lan Manager Key      (0x00000080)    Negotiate NTLM2 Key            (0x00080000)    Negotiate 128                  (0x20000000)    Negotiate Key Exchange         (0x40000000)    Negotiate 56                   (0x80000000)4e544c4d535350000100000037820000000000000000000000000000000000004e544c4d53535000    "NTLMSSP"01000000            Type 1 message37820000            Flags    Negotiate Unicode              (0x00000001)    Negotiate OEM                  (0x00000002)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)0000000000000000    Supplied Domain header (empty, supplied credentials)0000000000000000    Supplied Workstation header (empty, supplied credentials)--------------------------------------------------------------------------------AcceptSecurityContext called with ASC_REQ_INTEGRITY and ASC_REQ_CONFIDENTIALITY.Produces Type 2 message:4e544c4d53535000020000000c000c003000000035828100b019d38bad875c9d0000000000000000460046003c00000054004500530054004e00540002000c0054004500530054004e00540001000c004d0045004d0042004500520003001e006d0065006d006200650072002e0074006500730074002e0063006f006d00000000004e544c4d53535000    "NTLMSSP"02000000            Type 2 message0c000c0030000000    Target Name header (length 12, offset 48)35828100            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Target Type Domain             (0x00010000)    Negotiate Target Info          (0x00800000)b019d38bad875c9d    Challenge0000000000000000    Context460046003c000000    Target Information header (length 70, length 60)54004500530054004e005400    Target Name ("TESTNT")Target Information block:    02000c00    NetBIOS Domain Name (length 12)    54004500530054004e005400    "TESTNT"    01000c00    NetBIOS Server Name (length 12)    4d0045004d00420045005200    "MEMBER"    03001e00    DNS Server Name (length 30)    6d0065006d006200650072002e0074006500730074002e0063006f006d00        "member.test.com"    00000000    Target Information Terminator--------------------------------------------------------------------------------InitializeSecurityContext called.  Produces a Type 3 message:4e544c4d5353500003000000180018006000000018001800780000000c000c0040000000080008004c0000000c000c005400000000000000900000003582800054004500530054004e00540074006500730074004d0045004d004200450052001879f60127f8a877022132ec221bcbf3ca016a9f76095606e6285df3287c5d194f84df1a94817c7282d09754b6f9e02a4e544c4d53535000    "NTLMSSP"03000000            Type 3 message1800180060000000    LM/LMv2 Response header (length 24, offset 96)1800180078000000    NTLM/NTLMv2 Response header (length 24, offset 120)0c000c0040000000    Domain Name header (length 12, offset 64)080008004c000000    User Name header (length 8, offset 76)0c000c0054000000    Workstation Name header (length 12, offset 84)0000000090000000    Session Key header (empty)35828000            Flags    Negotiate Unicode              (0x00000001)    Request Target                 (0x00000004)    Negotiate Sign                 (0x00000010)    Negotiate Seal                 (0x00000020)    Negotiate NTLM                 (0x00000200)    Negotiate Always Sign          (0x00008000)    Negotiate Target Info          (0x00800000)54004500530054004e005400                            Domain Name ("TESTNT")7400650073007400                                    User Name ("test")4d0045004d00420045005200                            Workstation Name ("MEMBER")1879f60127f8a877022132ec221bcbf3ca016a9f76095606    LM/LMv2 Responsee6285df3287c5d194f84df1a94817c7282d09754b6f9e02a    NTLM/NTLMv2 Response--------------------------------------------------------------------------------AcceptSecurityContext called to complete the server-side context.Server Context Export:40a42e7840a42e780000000000000000000000000000000008ee0b00    server context handle dwUpper35828101    flags0000000000000000e8290900e8290900682a0900682a09000000000000000000d002000000000000000000000000000000000000000000000200000000000000ffffffffffffff7f20010000ae33a32dca8c9821844f740d5b3f4d6c    outbound signing keyae33a32dca8c9821844f740d5b3f4d6c    inbound verifying keyae33a32dca8c9821844f740d5b3f4d6c    outbound encrypting keyae33a32dca8c9821844f740d5b3f4d6c    inbound decrypting 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    "TESTNT/test"ntlmHash = md4(password) = 0x3b1b47e42e0463276e3ded6cef349f93NTLMUserSessionKey = md4(ntlmHash) = 0xae33a32dca8c9821844f740d5b3f4d6cKey is *not* weakened (NTLM1 only weakens Lan Manager Session Keys).Called MakeSignature on the server-side context for message"0x0102030405060708".Yields signature:0100000090010700087de41e039ae5c5CRC32(0x0102030405060708) = 0xc588ca3fSequence number is 0.0x00000000 + crc32 + seqnum = 0x00000000c588ca3f00000000RC4(key, 0x00000000c588ca3f00000000) = 0x20961389087de41e039ae5c5version num + first 4 bytes overwritten with counter value (0x90010700 here):0100000090010700087de41e039ae5c5 = signature--------------------------------------------------------------------------------Called EncryptMessage twice on the server-side context for message"0x0102030405060708".Yields encrypted messages:3ec555aea59eb55001000000a0030700f64393466a9317f71caf3c9a114ca2f4010000008803070095c1958123ecafcesame RC4 cipher is used from previous signing operation (i.e., not reset):RC4(0x0102030405060708) = sealed message = 0x3ec555aea59eb550trailer buffer gets signature; again uses same RC4 cipher(sequence number is now 1 because of previous signing):RC4(0x00000000c588ca3f01000000) = 0x8e8adf2bf64393466a9317f7version num + first 4 bytes overwritten w/counter (0xa0030700):01000000a0030700f64393466a9317f7 = trailer signaturesecond message is same:RC4(0x0102030405060708) = sealed message = 0x1caf3c9a114ca2f4trailer buffer signature with sequence 2:RC4(0x00000000c588ca3f02000000) = 0xf23fc1e495c1958123ecafceversion num + first 4 bytes overwritten w/counter (0x88030700)010000008803070095c1958123ecafce = trailer signature

The NTLM Authentication Protocol and Security Support Provider

The NTLM Authentication Protocol and Security Support Provider

Abstract

Contents

What is NTLM?

NTLM Terminology

The NTLM Message Header Layout

The NTLM Flags

The Type 1 Message

Type 1 Message Example

The Type 2 Message

Type 2 Message Example

The Type 3 Message

Name Variations

Responding to the Challenge

The LM Response

The NTLM Response

The NTLMv2 Response

The LMv2 Response

The NTLM2 Session Response

The Anonymous Response

Type 3 Message Example

NTLM Version 2

NTLMSSP and SSPI

Local Authentication

Datagram Authentication

Session Security - Signing & Sealing Concepts

The LM User Session Key

The NTLM User Session Key

The LMv2 User Session Key

The NTLMv2 User Session Key

The NTLM2 Session Response User Session Key

The Null User Session Key

The Lan Manager Session Key

Key Exchange

Key Weakening

NTLM1 Session Security

Master Key Negotiation

Key Exchange

Key Weakening

Signing

NTLM2 Session Security

Master Key Negotiation

Key Exchange

Key Weakening

Signing

Sealing

Miscellaneous Session Security Topics

Datagram Signing & Sealing

Appendix A: Links and References

"Dummy" Signing

Subkey Generation

NTLM2 Key Derivation

Sealing

NTLM1 Key Derivation

The User Session Key

Appendix B: Application Protocol Usage of NTLM

NTLM HTTP Authentication

NTLM POP3 Authentication

NTLM IMAP Authentication

NTLM SMTP Authentication

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the LM User Session Key

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 56-bit Lan Manager Session Key

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key

NTLMv1 Datagram-Style Authentication; NTLM1 Signing and Sealing Using the 40-bit Lan Manager Session Key With Key Exchange Negotiated

NTLMv1 Authentication; NTLM1 "Dummy" Signing and Sealing Using the NTLM User Session Key

NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 128-bit NTLM2 Session Response User Session Key With Key Exchange Negotiated

NTLM2 Session Response Authentication; NTLM2 Signing and Sealing Using the 40-bit NTLM2 Session Response User Session Key

NTLMv2 Authentication; NTLM1 Signing and Sealing Using the 40-bit NTLMv2 User Session Key

NTLMv2 Authentication; NTLM2 Signing and Sealing Using the 56-bit NTLMv2 User Session Key

Anonymous NTLMv1 Authentication; NTLM2 Signing and Sealing Using the 128-bit Null User Session Key With Key Exchange Negotiated

Local NTLMv1 Authentication; NTLM2 Signing and Sealing Using an Unknown Session Key With Key Exchange Negotiated (Analysis Incomplete)

Appendix D: Java Implementation of the Type 3 Response Calculations

Appendix C: Sample NTLMSSP Operation Decompositions

NTLMv1 Authentication; NTLM1 Signing and Sealing Using the NTLM User Session Key