Full Disclosure mailing list archives

Re: Swen Really Sucks


From: Evan Borgstrom <evan.borgstrom () ca mci com>
Date: 24 Sep 2003 10:59:50 -0400

http://tmda.sourceforge.net

Blacklist centric message system.

I haven't seen a single swen message yet. It doesn't solve the bandwidth
problem but at least it solves the problem of the messages appearing in
your inbox.

On Wed, 2003-09-24 at 03:29, Peter Busser wrote:
Hi!

Therefore, no IP, e-mail, or domain filter will solve the problem
completely without filtering every single possible permutation of From:
address that the virus spits out...

I use several procmail rules to filter out domains (microsoft.com, msdn.com,
etc.) in From: and From, To: (e.g. microsoft.com) and certain words in the
subject (e.g. Microsoft). Since the virus depends on looking like an authentic
message, it can't do too much randomisation of the domains and subject lines.
Of course the filtering is not perfect, but it still reduces the number of
virus messages hitting the inbox.

Removing messages with an executable attachment will also help of course.
Except with the messages sent to mailing lists that remove attachments
alltogether.

and using the "From" address rather than
the "From:" address for the filter doesn't work, either, because the "From"
address appears to be a different non-randomized e-mail address, possibly the
real e-mail address of the infected victim (? haven't read any forensic
analysis on this point yet...)

Does this imply that your e-mail filter does not understand regular
expressions?

Groetjes,
Peter Busser

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