OpenSSL Security Advisory [26 Jan 2017]
========================================

Truncated packet could crash via OOB read (CVE-2017-3731)
=========================================================

Severity: Moderate

If an SSL/TLS server or client is running on a 32-bit host, and a specific
cipher is being used, then a truncated packet can cause that server or client
to perform an out-of-bounds read, usually resulting in a crash.

For OpenSSL 1.1.0, the crash can be triggered when using CHACHA20/POLY1305;
users should upgrade to 1.1.0d

For Openssl 1.0.2, the crash can be triggered when using RC4-MD5; users who have
not disabled that algorithm should update to 1.0.2k

This issue was reported to OpenSSL on 13th November 2016 by Robert Święcki of
Google. The fix was developed by Andy Polyakov of the OpenSSL development team.

Bad (EC)DHE parameters cause a client crash (CVE-2017-3730)
===========================================================

Severity: Moderate

If a malicious server supplies bad parameters for a DHE or ECDHE key exchange
then this can result in the client attempting to dereference a NULL pointer
leading to a client crash. This could be exploited in a Denial of Service
attack.

OpenSSL 1.1.0 users should upgrade to 1.1.0d

This issue does not affect OpenSSL version 1.0.2.

Note that this issue was fixed prior to it being recognised as a security
concern. This means the git commit with the fix does not contain the CVE
identifier. The relevant fix commit can be identified by commit hash efbe126e3.

This issue was reported to OpenSSL on 14th January 2017 by Guido Vranken. The
fix was developed by Matt Caswell of the OpenSSL development team.

BN_mod_exp may produce incorrect results on x86_64 (CVE-2017-3732)
==================================================================

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.

UPDATE 31 Jan 2017.  The original text said
    For example this can occur by
    default in OpenSSL DHE based SSL/TLS ciphersuites.
This is not true.  DHE key re-use was removed by commit c5b831f for 1.0.2
or commit ffaef3f for 1.1.0 on 17 December 2015

Note: This issue is very similar to CVE-2015-3193 but must be treated as
a separate problem.

OpenSSL 1.1.0 users should upgrade to 1.1.0d
OpenSSL 1.0.2 users should upgrade to 1.0.2k

This issue was reported to OpenSSL on 15th January 2017 by the OSS-Fuzz project.
The fix was developed by Andy Polyakov of the OpenSSL development team.

Montgomery multiplication may produce incorrect results (CVE-2016-7055)
=======================================================================

Severity: Low

This issue was previously fixed in 1.1.0c and covered in security advisory
https://www.openssl.org/news/secadv/20161110.txt

OpenSSL 1.0.2 users should upgrade to 1.0.2k


Note
====

Support for version 1.0.1 ended on 31st December 2016. Support for versions
0.9.8 and 1.0.0 ended on 31st December 2015. Those versions are no longer
receiving security updates.

References
==========

URL for this Security Advisory:
https://www.openssl.org/news/secadv/20170126.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/policies/secpolicy.html