USN-2912-1: libssh vulnerabilities

Ubuntu Security Notice USN-2912-1

23rd February, 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 version:

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

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-2015-3146, CVE-2016-0739