7.5 - USN-2966-1

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 OpenSSH.

Software Description: - openssh: secure shell (SSH) for secure access to remote machines

Details:

Shayan Sadigh discovered that OpenSSH incorrectly handled environment files when the UseLogin feature is enabled. A local attacker could use this issue to gain privileges. (CVE-2015-8325)

Ben Hawkes discovered that OpenSSH incorrectly handled certain network traffic. A remote attacker could possibly use this issue to cause OpenSSH to crash, resulting in a denial of service. This issue only applied to Ubuntu 15.10. (CVE-2016-1907)

Thomas Hoger discovered that OpenSSH incorrectly handled untrusted X11 forwarding when the SECURITY extension is disabled. A connection configured as being untrusted could get switched to trusted in certain scenarios, contrary to expectations. (CVE-2016-1908)

It was discovered that OpenSSH incorrectly handled certain X11 forwarding data. A remote authenticated attacker could possibly use this issue to bypass certain intended command restrictions. (CVE-2016-3115)

Update instructions:

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

Ubuntu 15.10:
openssh-server 1:6.9p1-2ubuntu0.2

Ubuntu 14.04 LTS:
openssh-server 1:6.6p1-2ubuntu2.7

Ubuntu 12.04 LTS:
openssh-server 1:5.9p1-5ubuntu1.9

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

References:
http://www.ubuntu.com/usn/usn-2966-1
CVE-2015-8325, CVE-2016-1907, CVE-2016-1908, CVE-2016-3115

Package Information:
https://launchpad.net/ubuntu/+source/openssh/1:6.9p1-2ubuntu0.2
https://launchpad.net/ubuntu/+source/openssh/1:6.6p1-2ubuntu2.7
https://launchpad.net/ubuntu/+source/openssh/1:5.9p1-5ubuntu1.9