============================================================================
Ubuntu Security Notice USN-2912-1
February 23, 2016

libssh vulnerabilities
============================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 15.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in libssh.

Software Description:
- libssh: A tiny C SSH library

Details:

Mariusz Ziulek discovered that libssh incorrectly handled certain packets.
A remote attacker could possibly use this issue to cause libssh to crash,
resulting in a denial of service.
(CVE-2015-3146)

Aris Adamantiadis discovered that libssh incorrectly generated ephemeral
secret keys of 128 bits instead of the recommended 1024 or 2048 bits when
using the diffie-hellman-group1 and diffie-hellman-group14 methods. If a
remote attacker were able to perform a man-in-the-middle attack, this flaw
could be exploited to view sensitive information. (CVE-2016-0739)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 15.10:
  libssh-4                        0.6.3-3ubuntu3.2

Ubuntu 14.04 LTS:
  libssh-4                        0.6.1-0ubuntu3.3

Ubuntu 12.04 LTS:
  libssh-4                        0.5.2-1ubuntu0.12.04.6

In general, a standard system update will make all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-2912-1
  CVE-2015-3146, CVE-2016-0739

Package Information:
  https://launchpad.net/ubuntu/+source/libssh/0.6.3-3ubuntu3.2
  https://launchpad.net/ubuntu/+source/libssh/0.6.1-0ubuntu3.3
  https://launchpad.net/ubuntu/+source/libssh/0.5.2-1ubuntu0.12.04.6