An Intel Microcode security update has been released for Ubuntu Linux 20.04 LTS, 19.10, 18.04 LTS, 16.04 LTS, and 14.04 ESM.

USN-4385-1: Intel Microcode vulnerabilities

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Ubuntu Security Notice USN-4385-1
June 09, 2020

intel-microcode vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 19.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in Intel Microcode.

Software Description:
- intel-microcode: Processor microcode for Intel CPUs

Details:

It was discovered that memory contents previously stored in
microarchitectural special registers after RDRAND, RDSEED, and SGX EGETKEY
read operations on Intel client and Xeon E3 processors may be briefly
exposed to processes on the same or different processor cores. A local
attacker could use this to expose sensitive information. (CVE-2020-0543)

It was discovered that on some Intel processors, partial data values
previously read from a vector register on a physical core may be propagated
into unused portions of the store buffer. A local attacker could possible
use this to expose sensitive information. (CVE-2020-0548)

It was discovered that on some Intel processors, data from the most
recently evicted modified L1 data cache (L1D) line may be propagated into
an unused (invalid) L1D fill buffer. A local attacker could possibly use
this to expose sensitive information. (CVE-2020-0549)

Update instructions:

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

Ubuntu 20.04 LTS:
intel-microcode 3.20200609.0ubuntu0.20.04.0

Ubuntu 19.10:
intel-microcode 3.20200609.0ubuntu0.19.10.0

Ubuntu 18.04 LTS:
intel-microcode 3.20200609.0ubuntu0.18.04.0

Ubuntu 16.04 LTS:
intel-microcode 3.20200609.0ubuntu0.16.04.0

Ubuntu 14.04 ESM:
intel-microcode 3.20200609.0ubuntu0.14.04.0

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

References:
  https://usn.ubuntu.com/4385-1
CVE-2020-0543, CVE-2020-0548, CVE-2020-0549,
  https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SRBDS

Package Information:
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20200609.0ubuntu0.20.04.0
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20200609.0ubuntu0.19.10.0
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20200609.0ubuntu0.18.04.0
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20200609.0ubuntu0.16.04.0