USN-3690-2: AMD Microcode regression

05 July 2018

The system could be made to expose sensitive information.

Releases

Packages

  • 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

After a standard system update you need to reboot your computer to make
all the necessary changes.