RE: suspicious firewall rules in WinXP firewall

["David Gillett" <gillettdavid () fhda edu>]

  One of the worst shareware infections we've seen here was
redirecting all DNS traffic for the infected machine to a 
site in Eastern Europe.  When that site got taken down, DNS
resolution for the client stopped (which is what you're seeing),
and that's how we got the ticket to investigate.

David Gillett
 

> -----Original Message-----
> From: belka () att net [mailto:belka () att net] 
> Sent: Friday, June 30, 2006 1:32 PM
> To: incidents () securityfocus com
> Subject: suspicious firewall rules in WinXP firewall
>
> While setting a port for Symantec to query XP Pro 
> workstations for virus updates, I noticed two machines that 
> had firewall rules (exceptions in WinXP firewall parlance) 
> that were in unreadable charcaters, such as an asian font set 
> that couldn't be displayed. The rule name was in blocks or in 
> other unreadable characters.  The user of these two 
> workstations is notorious for downloading asian TV shows over 
> bit torrent, and visiting anime and other asian sites.
>
> I deleted the two firewall rules (DOH! I should have just 
> disabled them) and now IE and Mozilla browsers do not work at 
> all.  I can ping out of these two machines, and as long as I 
> use an IP address, these machines can ping anywhere in the 
> Internet.  However, if any call to DNS is requires, either 
> with a browser or ICMP, it fails.
>
> Has anyone had a similar experience or seen this kind of 
> behavior.  My fear is that one of the "special Korean 
> download programs" that this user admits installing has 
> altered the browser or -- even worse - the XP TCP/IP stack 
> with hooks into a trojan or spyware product.  I tried 
> disabling the firewall to allow all traffic in and out, but 
> to no effect.  No DNS functionality.  My packet traces are 
> inconclusive and my IDS is not alerting on anything in or out 
> of these two work stations.
>
> Any ideas?  At this point I know I am going to have to 
> reload, but from a forensic stand point, I am curious if any 
> one else has seen this kind of beavior before.
>
> Thanks.
>
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