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
3.2.x / master:
In tree, should contain this fix.
Pidgin, Empathy and Telepathy can't connect to Google Talk anymore after upgrading to gnutls-3.1.7, please see bug 455800 for details.
(In reply to comment #2)
> In tree, should contain this fix.
Thanks, Alon. May we proceed to stabilize =net-libs/gnutls-2.12.23 ?
(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.
Arches, please test and mark stable:
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"
Stable for HPPA.
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.
GLSA request filed.
m68k -> ~ only, removing from CC. Maintainers unCC'd themselves, did the cleanup myself.
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).