oss-security - Re: CVE id request: devotee (debian vote engine) cryptographically weak random numbers permit discovery of secret ballot submissions

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Date: Fri, 18 May 2012 16:39:42 -0600
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security@...ts.openwall.com
CC: Michael Gilbert <mgilbert@...ian.org>
Subject: Re: CVE id request: devotee (debian vote engine) cryptographically
 weak random numbers permit discovery of secret ballot submissions

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Hash: SHA1

On 05/18/2012 03:48 PM, Michael Gilbert wrote:
> Hi,
> 
> It has been disclosed [0] that the debian vote engine (devotee)
> [1] uses cryptographically weak pseudo-random numbers (intended to
> be 48-bit, but really only 32-bit due to the use of a 32-bit seed
> feeding the 48-bit number generator) to generate ballot secret
> monikers.  This allows unprivileged persons to brute force the
> contents of presumably secret election ballots, and makes it
> possible to calculate the contents of secret voter ballots in all
> past debian elections.
> 
> Ideally, devotee should use a random secret moniker with fully 64
> (or preferably 128) bits that would require years rather than
> minutes or days to brute force [2].
> 
> The source also uses /dev/urandom, which has less entropy than
> /dev/random.
> 
> Please assign an id for this issue.
> 
> Thanks, Mike
> 
> [0] https://lists.debian.org/debian-devel/2012/04/msg00528.html [1]
> http://anonscm.debian.org/gitweb/?p=users/srivasta/debian/devotee.git
>
> 
[2]
http://www.codinghorror.com/blog/2006/07/brute-force-key-attacks-are-for-dummies.html

This appears to be a service more than software, and although the
source is available (see git link) it appears to be out of date?

http://lists.debian.org/debian-www/2012/04/msg00200.html

Can you confirm the vulnerability is in the software you linked to,
and that this has actually been downloaded/used outside of Debian?


- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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