防止常见XSS 过滤 SQL注入 JAVA过滤器filter

XSS : 跨站脚本攻击(Cross Site Scripting)，为不和层叠样式表(Cascading Style Sheets, CSS)的缩写混淆，故将跨站脚本攻击缩写为XSS。恶意攻击者往Web页面里插入恶意html代码，当用户浏览该页之时，嵌入其中Web里面的html代码会被执行，从而达到恶意攻击用户的特殊目的。

sql注入
所谓SQL注入，就是通过把SQL命令插入到Web表单提交或输入域名或页面请求的查询字符串，最终达到欺骗服务器执行恶意的SQL命令。具体来说，它是利用现有应用程序，将（恶意）的SQL命令注入到后台数据库引擎执行的能力，它可以通过在Web表单中输入（恶意）SQL语句得到一个存在安全漏洞的网站上的数据库，而不是按照设计者意图去执行SQL语句。

1、首先配置web.xml，添加如下配置信息：

<!-- 解决xss & sql漏洞 --><filter><filter-name>xssAndSqlFilter</filter-name><filter-class>com.cup.cms.web.framework.filter.XssAndSqlFilter</filter-class></filter><!-- 解决xss & sql漏洞 --><filter-mapping><filter-name>xssAndSqlFilter</filter-name><url-pattern>*</url-pattern></filter-mapping>

2、编写过滤器

/** *  */package com.cup.cms.web.framework.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServletRequest;/** * @Author hithedy * @Date 2016年2月2日 * @Time 下午2:01:53 */public class XssAndSqlFilter implements Filter {@Overridepublic void destroy() {// TODO Auto-generated method stub}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {XssAndSqlHttpServletRequestWrapper xssRequest = new XssAndSqlHttpServletRequestWrapper((HttpServletRequest) request);chain.doFilter(xssRequest, response);}@Overridepublic void init(FilterConfig arg0) throws ServletException {// TODO Auto-generated method stub}}

3、包装器

/** *  */package com.cup.cms.web.framework.filter;import java.util.regex.Pattern;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRequestWrapper;/** * @Author hithedy * @Date 2016年2月2日 * @Time 下午2:03:19 */public class XssAndSqlHttpServletRequestWrapper extends HttpServletRequestWrapper {HttpServletRequest orgRequest = null;public XssAndSqlHttpServletRequestWrapper(HttpServletRequest request) {super(request);orgRequest = request;}/** * 覆盖getParameter方法，将参数名和参数值都做xss & sql过滤。<br/> * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取<br/> * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖 */@Overridepublic String getParameter(String name) {String value = super.getParameter(xssEncode(name));if (value != null) {value = xssEncode(value);}return value;}/** * 覆盖getHeader方法，将参数名和参数值都做xss & sql过滤。<br/> * 如果需要获得原始的值，则通过super.getHeaders(name)来获取<br/> * getHeaderNames 也可能需要覆盖 */@Overridepublic String getHeader(String name) {String value = super.getHeader(xssEncode(name));if (value != null) {value = xssEncode(value);}return value;}/** * 将容易引起xss & sql漏洞的半角字符直接替换成全角字符 *  * @param s * @return */private static String xssEncode(String s) {if (s == null || s.isEmpty()) {return s;}else{s = stripXSSAndSql(s);}StringBuilder sb = new StringBuilder(s.length() + 16);for (int i = 0; i < s.length(); i++) {char c = s.charAt(i);switch (c) {case '>':sb.append("＞");// 转义大于号break;case '<':sb.append("＜");// 转义小于号break;case '\'':sb.append("＇");// 转义单引号break;case '\"':sb.append("＂");// 转义双引号break;case '&':sb.append("＆");// 转义&break;case '#':sb.append("＃");// 转义#break;default:sb.append(c);break;}}return sb.toString();}/** * 获取最原始的request *  * @return */public HttpServletRequest getOrgRequest() {return orgRequest;}/** * 获取最原始的request的静态方法 *  * @return */public static HttpServletRequest getOrgRequest(HttpServletRequest req) {if (req instanceof XssAndSqlHttpServletRequestWrapper) {return ((XssAndSqlHttpServletRequestWrapper) req).getOrgRequest();}return req;}/** *  * 防止xss跨脚本攻击（替换，根据实际情况调整） */public static String stripXSSAndSql(String value) {if (value != null) {// NOTE: It's highly recommended to use the ESAPI library and// uncomment the following line to// avoid encoded attacks.// value = ESAPI.encoder().canonicalize(value);// Avoid null characters/**value = value.replaceAll("", "");***/// Avoid anything between script tagsPattern scriptPattern = Pattern.compile("<[\r\n| | ]*script[\r\n| | ]*>(.*?)</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);value = scriptPattern.matcher(value).replaceAll("");// Avoid anything in a src="http://www.yihaomen.com/article/java/..." type of e-xpressionscriptPattern = Pattern.compile("src[\r\n| | ]*=[\r\n| | ]*[\\\"|\\\'](.*?)[\\\"|\\\']", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);value = scriptPattern.matcher(value).replaceAll("");// Remove any lonesome </script> tagscriptPattern = Pattern.compile("</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);value = scriptPattern.matcher(value).replaceAll("");// Remove any lonesome <script ...> tagscriptPattern = Pattern.compile("<[\r\n| | ]*script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);value = scriptPattern.matcher(value).replaceAll("");// Avoid eval(...) expressionsscriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);value = scriptPattern.matcher(value).replaceAll("");// Avoid e-xpression(...) expressionsscriptPattern = Pattern.compile("e-xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);value = scriptPattern.matcher(value).replaceAll("");// Avoid javascript:... expressionsscriptPattern = Pattern.compile("javascript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);value = scriptPattern.matcher(value).replaceAll("");// Avoid vbscript:... expressionsscriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);value = scriptPattern.matcher(value).replaceAll("");// Avoid onload= expressionsscriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);value = scriptPattern.matcher(value).replaceAll("");}return value;}}

能够防止常见的XSS和SQL注入。