USN-3690-2: AMD Microcode regression

5 July 2018

amd64-microcode regression

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

  • Ubuntu 14.04 LTS

Summary

The system could be made to expose sensitive information.

Software Description

  • amd64-microcode - Processor microcode firmware for AMD CPUs

Details

USN-3690-1 provided updated microcode for AMD processors to address CVE-2017-5715 (aka Spectre). Unfortunately, the update caused some systems to fail to boot. This update reverts the update for Ubuntu 14.04 LTS.

We apologize for the inconvenience.

Original advisory details:

Jann Horn discovered that microprocessors utilizing speculative execution and branch prediction may allow unauthorized memory reads via sidechannel attacks. This flaw is known as Spectre. A local attacker could use this to expose sensitive information, including kernel memory.

This update provides the microcode updates for AMD 17H family processors required for the corresponding Linux kernel updates.

Update instructions

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

Ubuntu 14.04 LTS
amd64-microcode - 3.20180524.1~ubuntu0.14.04.2+really20130710.1

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.

References