On January 28, in a security notice Canonical published details about a libssh vulnerability for its Ubuntu 12.10, Ubuntu 12.04 LTS, Ubuntu 11.10, and Ubuntu 10.04 LTS operating systems.
According to Canonical
, libssh could have been made to crash, if it received specially crafted network traffic.
It was discovered that libssh incorrectly handled certain negotiation requests. A remote attacker could use this to cause libssh to crash, resulting in a denial of service.
The security flaws can be fixed if you upgrade your system(s) to the latest libssh-4 package, specific to each operating system. To apply the update, run the Update Manager application.
In general, a standard system update will make all the necessary changes. A system restart won't be necessary to implement the changes.
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades