Bug 455560 (CVE-2013-1619) – <net-libs/gnutls-{2.12.23,3.1.8}: TLS CBC padding timing attack (CVE-2013-1619)

• Product: Gentoo Security
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2013-02-05 09:29:24 UTC]

From $URL :

A flaw in how TLS/DTLS, when CBC-mode encryption is used, communicates was reported.  This 
vulnerability can allow for a Man-in-the-Middle attacker to recover plaintext from a TLS/DTLS 
connection, when CBC-mode encryption is used.

This flaw is in the TLS specification, and not a bug in a specific implementation (as such, it 
affects nearly all implementations).  As such, it affects all TLS and DTLS implementations that are 
compliant with TLS 1.1 or 1.2, or with DTLS 1.0 or 1.2.  It also applies to implementations of SSL 
3.0 and TLS 1.0 that incorporate countermeasures to deal with previous padding oracle attacks.  All 
TLS/DTLS ciphersuites that include CBC-mode encryption are potentially vulnerable.

The paper indicates that with OpenSSL, a full plaintext recovery attack is possible, and with 
GnuTLS, a partial plaintext recovery is possible (recovering up to 4 bits of the last byte in any 
block of plaintext).

To perform a successful attack, when TLS is used, a large number of TLS sessions are required 
(target plaintext must be sent repeatedly in the same position in the plaintext stream across the 
sessions).  For DTLS, a successful attack can be carried out in a single session.  The attacker 
must also be located close to the machine being attacked.

Further details are noted in the paper.

Current status of fixes in various implementations:

* OpenSSL has a patch in development
* NSS has a patch in development
* GnuTLS is fixed in versions 2.12.23, 3.0.28, and 3.1.7
* PolarSSL is fixed in version 1.2.5
* BouncyCastle has a patch that will be included in the forthcoming 1.48 version


External References:

http://www.isg.rhul.ac.uk/tls/
http://www.isg.rhul.ac.uk/tls/TLStiming.pdf
http://www.gnutls.org/security.html#GNUTLS-SA-2013-1
https://polarssl.org/tech-updates/releases/polarssl-1.2.5-released

[Comment 1 Agostino Sarubbo 2013-02-05 09:31:06 UTC]

GnuTLS fix:

2.12.x:
https://gitorious.org/gnutls/gnutls/commit/458c67cf98740e7b12404f6c30e0d5317d56fd30
https://gitorious.org/gnutls/gnutls/commit/93b7fcfa3297a9123630704668b2946f602b910e

3.0.x:
https://gitorious.org/gnutls/gnutls/commit/8dc2822966f64dd9cf7dde9c7aacd80d49d3ffe5

3.2.x / master:
https://gitorious.org/gnutls/gnutls/commit/328ee22c1b3951e060c7124c7cb1cee592c59bc0

[Comment 2 Alon Bar-Lev (RETIRED) 2013-02-05 10:42:32 UTC]

gnutls-2.12.23
gnutls-3.1.7

In tree, should contain this fix.

[Comment 3 Ronny Perinke 2013-02-08 22:06:08 UTC]

Pidgin, Empathy and Telepathy can't connect to Google Talk anymore after upgrading to gnutls-3.1.7, please see bug 455800 for details.

[Comment 4 Sean Amoss (RETIRED) 2013-02-25 22:38:37 UTC]

(In reply to comment #2)
> gnutls-2.12.23
> gnutls-3.1.7
> 
> In tree, should contain this fix.

Thanks, Alon. May we proceed to stabilize =net-libs/gnutls-2.12.23 ?

[Comment 5 Alon Bar-Lev (RETIRED) 2013-02-26 07:53:04 UTC]

(In reply to comment #4)
> (In reply to comment #2)
> > gnutls-2.12.23
> > gnutls-3.1.7
> > 
> > In tree, should contain this fix.
> 
> Thanks, Alon. May we proceed to stabilize =net-libs/gnutls-2.12.23 ?

Seems so, no issues so far.

FYI the gnutls-3.1.7 was broken, gnutls-3.1.8 was released.

Thanks!

[Comment 6 Sean Amoss (RETIRED) 2013-03-04 00:57:25 UTC]

Arches, please test and mark stable:
=net-libs/gnutls-2.12.23
Target KEYWORDS: "alpha amd64 arm hppa ia64 m68k ~mips ppc ppc64 s390 sh sparc x86 ~amd64-fbsd ~x86-fbsd ~x86-interix ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~x86-macos ~sparc-solaris ~x86-solaris"

[Comment 7 Agostino Sarubbo 2013-03-04 09:11:19 UTC]

amd64 stable

[Comment 8 Agostino Sarubbo 2013-03-04 09:20:49 UTC]

x86 stable

[Comment 9 Jeroen Roovers (RETIRED) 2013-03-04 15:36:48 UTC]

Stable for HPPA.

[Comment 10 Brent Baude (RETIRED) 2013-03-04 18:16:39 UTC]

ppc done

[Comment 11 GLSAMaker/CVETool Bot 2013-03-04 23:37:18 UTC]

CVE-2013-1619 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2013-1619):
  The TLS implementation in GnuTLS before 2.12.23, 3.0.x before 3.0.28, and
  3.1.x before 3.1.7 does not properly consider timing side-channel attacks on
  a noncompliant MAC check operation during the processing of malformed CBC
  padding, which allows remote attackers to conduct distinguishing attacks and
  plaintext-recovery attacks via statistical analysis of timing data for
  crafted packets, a related issue to CVE-2013-0169.

[Comment 12 Agostino Sarubbo 2013-03-06 10:23:06 UTC]

sh stable

[Comment 13 Agostino Sarubbo 2013-03-08 17:45:18 UTC]

arm stable

[Comment 14 Agostino Sarubbo 2013-03-09 12:03:59 UTC]

ppc64 stable

[Comment 15 Agostino Sarubbo 2013-03-09 13:33:36 UTC]

alpha stable

[Comment 16 Agostino Sarubbo 2013-03-09 14:24:32 UTC]

ia64 stable

[Comment 17 Agostino Sarubbo 2013-03-09 19:08:21 UTC]

sparc stable

[Comment 18 Agostino Sarubbo 2013-03-10 16:19:26 UTC]

s390 stable

[Comment 19 Tobias Heinlein (RETIRED) 2013-03-24 19:33:16 UTC]

GLSA request filed.

[Comment 20 Alon Bar-Lev (RETIRED) 2013-03-30 23:14:15 UTC]

crypto done.

[Comment 21 Chris Reffett (RETIRED) 2013-09-22 14:07:12 UTC]

m68k -> ~ only, removing from CC. Maintainers unCC'd themselves, did the cleanup myself.

[Comment 22 GLSAMaker/CVETool Bot 2013-10-28 11:53:27 UTC]

This issue was resolved and addressed in
 GLSA 201310-18 at http://security.gentoo.org/glsa/glsa-201310-18.xml
by GLSA coordinator Sergey Popov (pinkbyte).