RE: suspicious firewall rules in WinXP firewall

["Darren Clarke" <mailcentre2 () gmail com>]

Did your packet traces show evidence of attempted connections to your
known DNS server when you attempted to browse a website?
What about the hosts file, any "suspicious" entries in there?
Lastly what about a proxy server running (or proxy settings that have
been modified in the browser)?

Regards,


-----Original Message-----
From: belka () att net [mailto:belka () att net]
Sent: Friday, June 30, 2006 9:32 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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