Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Fri, 27 Feb 2015 10:11:36 -0500
From: Daniel Kahn Gillmor <dkg@...thhorseman.net>
To: Florent Daigniere <florent.daigniere@...stmatta.com>, oss-security@...ts.openwall.com
Subject: dropbear and PuTTY missing DHE sanity checks  [was: Re: CVE request: RFC 4253 section 8 wooes]

On Fri 2015-02-27 06:59:57 -0500, Florent Daigniere wrote:

> RFC 4253 section 8 describes how the DiffieHellman exchange is done in
> SSH... It mandates a few sanity bound-checks (for both the values of
> exponents and exponentials) that some implementations are not doing...
>
> Can you please assign three CVEs for the following bugs?
>
> MATTA-2015-002 PuTTY
> will be fixed in the upcoming release (0.64 I think)
> - The exponential is not checked for trivial values
>
> MATTA-2015-001 Dropbox
                 ^^^^^^^ I'm pretty sure you mean dropbear here, based
                         on the links below.
                 
> fixed in: https://secure.ucc.asn.au/hg/dropbear/rev/a1e79ffa5862
> - The exponential is not checked for all trivial values (it just does
> what the RFC mandates, which is clearly not enough!)
> - The exponent picked might be a trivial value (this is theoretical more
> than anything else assuming the CSPRNG is working). It's a regression
> from 0.49
> (https://secure.ucc.asn.au/hg/dropbear/diff/00703f1df67a/random.c)

regards,

  --dkg

Powered by blists - more mailing lists

Your e-mail address:

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.