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Date:      Tue, 22 Jul 2008 17:52:42 +0200 (CEST)
From:      Oliver Fromme <olli@lurza.secnetix.de>
To:        freebsd-stable@FreeBSD.ORG
Subject:   Re: FreeBSD 7.1 and BIND exploit
Message-ID:  <200807221552.m6MFqgpm009488@lurza.secnetix.de>
In-Reply-To: <200807212219.QAA01486@lariat.net>

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Brett Glass wrote:
 > At 02:24 PM 7/21/2008, Kevin Oberman wrote:
 > 
 > > Don't forget that ANY server that caches data, including an end system
 > > running a caching only server is vulnerable.
 >
 > Actually, there is an exception to this. A "forward only"
 > cache/resolver is only as vulnerable as its forwarder(s). This is a
 > workaround for the vulnerability for folks who have systems that they
 > cannot easily upgrade: point at a trusted forwarder that's patched.
 >
 > We're also looking at using dnscache from the djbdns package.

I'm curious, is djbdns exploitable, too?  Does it randomize
the source ports of UDP queries?

 > Of course, all solutions that randomize ports are really just
 > "security by obscurity," because by shuffling ports you're hiding the
 > way to poison your cache... a little.

True, but there is currently no better solution, AFAIK.
The problem is inherent in the way DNS queries work.

Best regards
   Oliver

-- 
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

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"That's what I love about GUIs: They make simple tasks easier,
and complex tasks impossible."
        -- John William Chambless



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