Dailydave mailing list archives
Re: Re: Moot choices, a sort of DD media party
From: Florian Weimer <fw () deneb enyo de>
Date: Sat, 02 Jul 2005 15:30:39 +0200
* Aviram Jenik:
A while ago we found a problem in the SMTP standard ("SMTP fragmentation") that allowed SMTP gateway bypassing in a way similar to TCP fragmentation: http://www.securiteam.com/securitynews/5YP0A0K8CM.html We decided the right thing to do was to contact all the relevant vendors we could find in addition to CERT, and hope for the best. We were actually surprised for the better
Well, the underlying problem has nothing to do with SMTP. You try to protect a fragile parser B by sticking some parser A in front of it. In order to do this, A must have detailed knowledge of a wide variety of Bs, and in practice, there will always be discrepancies which can be used to bypass parser A. This is quite a frequent theme: ZIP archives and CRC mismatches, malformed Microsoft Office documents with macros, TCP segments with strange flags, HTTP requests with malformed headers, and so on. It's better to assume that security cannot be composed this way. _______________________________________________ Dailydave mailing list Dailydave () lists immunitysec com https://lists.immunitysec.com/mailman/listinfo/dailydave
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- Moot choices, a sort of DD media party Dave Aitel (Jul 01)
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- RE: Moot choices, a sort of DD media party Aleksander P. Czarnowski (Jul 01)
- Re: Moot choices, a sort of DD media party Rodney Thayer (Jul 01)
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- Re: Moot choices, a sort of DD media party Rodney Thayer (Jul 01)
- Re: Moot choices, a sort of DD media party Aviram Jenik (Jul 02)
- Re: Re: Moot choices, a sort of DD media party Florian Weimer (Jul 02)
- Re: Moot choices, a sort of DD media party Rodney Thayer (Jul 01)
- Re: Moot choices, a sort of DD media party Florian Weimer (Jul 02)
- RE: Moot choices, a sort of DD media party Cesar (Jul 01)
- Re: Moot choices, a sort of DD media party Matt Hargett (Jul 01)