USN-2966-1: OpenSSH vulnerabilities

Ubuntu Security Notice USN-2966-1

9th May, 2016

openssh 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 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 version:

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

To update your system, please follow these instructions:
https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2015-8325,

CVE-2016-1907,

CVE-2016-1908,

CVE-2016-3115

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