Several security issues were fixed in OpenSSL.
Samuel Weiser discovered that OpenSSL incorrectly handled DSA signing. An attacker could possibly use this issue to perform a timing side-channel attack and recover private DSA keys. (CVE-2018-0734)
6 December 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in OpenSSL.
Samuel Weiser discovered that OpenSSL incorrectly handled DSA signing. An attacker could possibly use this issue to perform a timing side-channel attack and recover private DSA keys. (CVE-2018-0734)
Samuel Weiser discovered that OpenSSL incorrectly handled ECDSA signing. An attacker could possibly use this issue to perform a timing side-channel attack and recover private ECDSA keys. This issue only affected Ubuntu 18.04 LTS and Ubuntu 18.10. (CVE-2018-0735)
Billy Bob Brumley, Cesar Pereida Garcia, Sohaib ul Hassan, Nicola Tuveri, and Alejandro Cabrera Aldaya discovered that Simultaneous Multithreading (SMT) architectures are vulnerable to side-channel leakage. This issue is known as "PortSmash". An attacker could possibly use this issue to perform a timing side-channel attack and recover private keys. (CVE-2018-5407)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.