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Re: Non existing attachments, more info
From: Jason Haar <Jason.Haar () trimble co nz>
Date: Wed, 20 Feb 2002 21:49:05 +1300

On Mon, Feb 18, 2002 at 10:02:17AM -0500, David F. Skoll wrote:
I initially made my scanner emulate the Outlook bug; now I see it's the
wrong thing to do.

Indeed.


I believe the only sane way to handle these kinds of malformed messages is:

1) Reject any message with suspicious characters in the headers (e.g.,
embedded CR's.)  It's pointless for a server-based scanner to try to
out-think all the different mail user agents out there.


Qmail-Scanner has done that since BadTrans came out. As you found out,
"fixing" the message isn't the solution. Instead block it as "suspicious".

I have 2 months worth of data on this, since Qmail-Scanner started blocking
lone CR in MIME headers, almost all messages stopped were viruses or spam.
The few that were "real" messages were from broken windows installs of
Squirrelmail...  (that's what you get when you edit php files with notepad I
suppose ;-)


http://qmail-scanner.sourceforge.net/

-- 
Cheers

Jason Haar

Information Security Manager
Trimble Navigation Ltd.
Phone: +64 3 9635 377 Fax: +64 3 9635 417


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