oss-security - Re: DNS vulnerability: other relevant software

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Date: Wed, 9 Jul 2008 14:36:10 +0100 (BST)
From: Mark J Cox <mjc@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Re: DNS vulnerability: other relevant software

> Additionally, Debian has noted (DSA 1605-1) that the GNU libc stub
> resolver could benefit from random query source ports as well, but
> no patches are currently available to implement this:

Note that GNU libc stub resolver when used with a recent kernel (2.6.24+) 
will give you random UDP source ports on each request because of this 
Linux commit:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=32c1da70810017a98aa6c431a5494a302b6b9a30

Vendors may with to consider backporting that kernel patch as an effective 
mitigation without requiring glibc changes (and with the advantage of 
being able to be have a customized range using ip_local_port_range etc)

Cheers, Mark

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