OpenSSL Security Advisory [3 Dec 2015] - Updated [4 Dec 2015]
=============================================================

[Updated 4 Dec 2015]: This advisory has been updated to include the details of
CVE-2015-1794, a Low severity issue affecting OpenSSL 1.0.2 which had a fix
included in the released packages but was missed from the advisory text.

NOTE: WE ANTICIPATE THAT 1.0.0t AND 0.9.8zh WILL BE THE LAST RELEASES FOR THE
0.9.8 AND 1.0.0 VERSIONS AND THAT NO MORE SECURITY FIXES WILL BE PROVIDED (AS
PER PREVIOUS ANNOUNCEMENTS). USERS ARE ADVISED TO UPGRADE TO LATER VERSIONS.

BN_mod_exp may produce incorrect results on x86_64 (CVE-2015-3193)
==================================================================

Severity: Moderate

There is a carry propagating bug in the x86_64 Montgomery squaring procedure. No
EC algorithms are affected. Analysis suggests that attacks against RSA and DSA
as a result of this defect would be very difficult to perform and are not
believed likely. Attacks against DH are considered just feasible (although very
difficult) because most of the work necessary to deduce information
about a private key may be performed offline. The amount of resources
required for such an attack would be very significant and likely only
accessible to a limited number of attackers. An attacker would
additionally need online access to an unpatched system using the target
private key in a scenario with persistent DH parameters and a private
key that is shared between multiple clients. For example this can occur by
default in OpenSSL DHE based SSL/TLS ciphersuites.

This issue affects OpenSSL version 1.0.2.

OpenSSL 1.0.2 users should upgrade to 1.0.2e

This issue was reported to OpenSSL on August 13 2015 by Hanno
Böck. The fix was developed by Andy Polyakov of the OpenSSL
development team.

Certificate verify crash with missing PSS parameter (CVE-2015-3194)
===================================================================

Severity: Moderate

The signature verification routines will crash with a NULL pointer dereference
if presented with an ASN.1 signature using the RSA PSS algorithm and absent
mask generation function parameter. Since these routines are used to verify
certificate signature algorithms this can be used to crash any certificate
verification operation and exploited in a DoS attack. Any application which
performs certificate verification is vulnerable including OpenSSL clients and
servers which enable client authentication.

This issue affects OpenSSL versions 1.0.2 and 1.0.1.

OpenSSL 1.0.2 users should upgrade to 1.0.2e
OpenSSL 1.0.1 users should upgrade to 1.0.1q

This issue was reported to OpenSSL on August 27 2015 by Loïc Jonas Etienne
(Qnective AG). The fix was developed by Dr. Stephen Henson of the OpenSSL
development team.

X509_ATTRIBUTE memory leak (CVE-2015-3195)
==========================================

Severity: Moderate

When presented with a malformed X509_ATTRIBUTE structure OpenSSL will leak
memory. This structure is used by the PKCS#7 and CMS routines so any
application which reads PKCS#7 or CMS data from untrusted sources is affected.
SSL/TLS is not affected.

This issue affects OpenSSL versions 1.0.2 and 1.0.1, 1.0.0 and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2e
OpenSSL 1.0.1 users should upgrade to 1.0.1q
OpenSSL 1.0.0 users should upgrade to 1.0.0t
OpenSSL 0.9.8 users should upgrade to 0.9.8zh

This issue was reported to OpenSSL on November 9 2015 by Adam Langley
(Google/BoringSSL) using libFuzzer. The fix was developed by Dr. Stephen
Henson of the OpenSSL development team.

Race condition handling PSK identify hint (CVE-2015-3196)
=========================================================

Severity: Low

If PSK identity hints are received by a multi-threaded client then
the values are wrongly updated in the parent SSL_CTX structure. This can
result in a race condition potentially leading to a double free of the
identify hint data.

This issue was fixed in OpenSSL 1.0.2d and 1.0.1p but has not been previously
listed in an OpenSSL security advisory. This issue also affects OpenSSL 1.0.0
and has not been previously fixed in an OpenSSL 1.0.0 release.

OpenSSL 1.0.2 users should upgrade to 1.0.2d
OpenSSL 1.0.1 users should upgrade to 1.0.1p
OpenSSL 1.0.0 users should upgrade to 1.0.0t

The fix for this issue can be identified in the OpenSSL git repository by commit
ids 3c66a669dfc7 (1.0.2), d6be3124f228 (1.0.1) and 1392c238657e (1.0.0).

The fix was developed by Dr. Stephen Henson of the OpenSSL development team.

Anon DH ServerKeyExchange with 0 p parameter (CVE-2015-1794)
============================================================

Severity: Low

If a client receives a ServerKeyExchange for an anonymous DH ciphersuite with
the value of p set to 0 then a seg fault can occur leading to a possible denial
of service attack.

This issue affects OpenSSL version 1.0.2.

OpenSSL 1.0.2 users should upgrade to 1.0.2e

This issue was reported to OpenSSL on August 3 2015 by Guy Leaver (Cisco). The
fix was developed by Matt Caswell of the OpenSSL development team.

Note
====

As per our previous announcements and our Release Strategy
(https://www.openssl.org/about/releasestrat.html), support for OpenSSL versions
1.0.0 and 0.9.8 will cease on 31st December 2015. No security updates for these
versions will be provided after that date. In the absence of significant
security issues being identified prior to that date, the 1.0.0t and 0.9.8zh
releases will be the last for those versions. Users of these versions are
advised to upgrade.


References
==========

URL for this Security Advisory:
https://www.openssl.org/news/secadv/20151203.txt

Note: the online version of the advisory may be updated with additional
details over time.

For details of OpenSSL severity classifications please see:
https://www.openssl.org/about/secpolicy.html