7.8 - USN-3061-1

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

- Ubuntu 16.04 LTS - 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:

Eddie Harari discovered that OpenSSH incorrectly handled password hashing when authenticating non-existing users. A remote attacker could perform a timing attack and enumerate valid users. (CVE-2016-6210)

Tomas Kuthan, Andres Rojas, and Javier Nieto discovered that OpenSSH did not limit password lengths. A remote attacker could use this issue to cause OpenSSH to consume resources, leading to a denial of service. (CVE-2016-6515)

Update instructions:

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

Ubuntu 16.04 LTS:
openssh-server 1:7.2p2-4ubuntu2.1

Ubuntu 14.04 LTS:
openssh-server 1:6.6p1-2ubuntu2.8

Ubuntu 12.04 LTS:
openssh-server 1:5.9p1-5ubuntu1.10

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

References:
http://www.ubuntu.com/usn/usn-3061-1
CVE-2016-6210, CVE-2016-6515

Package Information:
https://launchpad.net/ubuntu/+source/openssh/1:7.2p2-4ubuntu2.1
https://launchpad.net/ubuntu/+source/openssh/1:6.6p1-2ubuntu2.8
https://launchpad.net/ubuntu/+source/openssh/1:5.9p1-5ubuntu1.10