From owner-freebsd-security@FreeBSD.ORG  Tue Mar  2 08:13:42 2004
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From: Darren Reed <avalon@caligula.anu.edu.au>
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To: stb@lassitu.de (Stefan Bethke)
Date: Wed, 3 Mar 2004 03:13:38 +1100 (Australia/ACT)
In-Reply-To: <9CDEFA50-6C4F-11D8-9FC0-000393496BE8@lassitu.de> from "Stefan
	Bethke" at Mar 02, 2004 02:43:39 PM
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cc: freebsd-security@freebsd.org
Subject: Re: mbuf vulnerability
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In some mail from Stefan Bethke, sie said:
> 
> Am 01.03.2004 um 18:42 schrieb Mike Silbersack:
> > A specially constructed stateful firewall could be constructed to deal
> > with this DoS, but I'm certain that there's no way you could use ipf or
> > anything preexisting to do the job.

IPFilter v4 can prevent this attack with:

pass in .. proto tcp ... keep state(strict)

> OpenBSD's pf scrubbing should be helpful here. From the FAQ:
> > The scrub directive also reassembles fragmented packets, protecting 
> > some operating systems from some forms of attack.
> <http://www.openbsd.org/faq/pf/scrub.html>

Uh, no, "scrub" dosn't protect against this attack at all (or at least
not according to that web page.)

Darren