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Ubuntu Security Notice USN-2966-1
May 09, 2016

openssh vulnerabilities
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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:
  https://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