Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Wed, 30 Jan 2013 11:33:53 -0700
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security@...ts.openwall.com
CC: Florian Weimer <fweimer@...hat.com>,
        Salvatore Bonaccorso <carnil@...ian.org>
Subject: Re: CVE request: hs-tls: Basic constraints vulnerability

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 01/30/2013 03:59 AM, Florian Weimer wrote:
> On 01/20/2013 01:32 PM, Salvatore Bonaccorso wrote:
> 
>> For hs-tls (TLS/SSL implementation in haskell) it was announced
>> the following advisory[0]:
>> 
>> ----cut---------cut---------cut---------cut---------cut---------cut-----
>>
>> 
Hi cafe,
>> 
>> this is a security advisory for tls-extra < 0.6.1 which are all 
>> vulnerable to bad certificate validation.
>> 
>> Some part of the certificate validation procedure were missing 
>> (relying on the work-in-progress x509 v3 extensions), and because
>> of this anyone with a correct end-entity certificate can issue
>> certificate for any arbitrary domain, i.e. acting as a CA.
>> 
>> This problem has been fixed in tls-extra 0.6.1, and I advise
>> everyone to upgrade as soon as possible.
>> 
>> Despite a very serious flaw in the certificate validation, I'm
>> happy that the code is seeing some audits, and would want to
>> thanks Ertugrul S´┐Âylemez for the findings [1].
>> 
>> [1] https://github.com/vincenthz/hs-tls/issues/29 
>> ----cut---------cut---------cut---------cut---------cut---------cut-----
>
>> 
> I believe an alternative description of the impact is:
> hs-tls-extras does not check the Basic Constraints attribute of a
> certificate in certificate chain procession, and any certificate is
> treated as a CA certificate, which means that anyone who has a
> valid certificate can use it to sign another one (with an arbitrary
> subject DN/domain name embedded into it) and have it accepted by
> hs-tls.  This eventually allows MITM attacks on TLS connections.
> 
> Kurt, is this more to your liking? 8-)

Yup!

Please use CVE-2013-0243 for this issue.

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

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.13 (GNU/Linux)
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=DpBg
-----END PGP SIGNATURE-----

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.