An Intel Microcode security update has been released for Ubuntu Linux 14.04 ESM, 16.04 ESM, 18.04 LTS, 20.04 LTS, 20.10, and 21.04.

USN-4985-1: Intel Microcode vulnerabilities

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Ubuntu Security Notice USN-4985-1
June 09, 2021

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

- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM
- 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 some Intel processors may not properly invalidate
cache entries used by Intel Virtualization Technology for Directed I/O
(VT-d). This may allow a local user to perform a privilege escalation
attack. (CVE-2021-24489)

Joseph Nuzman discovered that some Intel processors may not properly apply
EIBRS mitigations (originally developed for CVE-2017-5715) and hence may
allow unauthorized memory reads via sidechannel attacks. A local attacker
could use this to expose sensitive information, including kernel
memory. (CVE-2020-24511)

Travis Downs discovered that some Intel processors did not properly flush
cache-lines for trivial-data values. This may allow an unauthorized user to
infer the presence of these trivial-data-cache-lines via timing sidechannel
attacks. A local attacker could use this to expose sensitive
information. (CVE-2020-24512)

It was discovered that certain Intel Atom processors could expose memory
contents stored in microarchitectural buffers. A local attacker could use
this to expose sensitive information. (CVE-2020-24513)

Update instructions:

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

Ubuntu 21.04:
intel-microcode 3.20210608.0ubuntu0.21.04.1

Ubuntu 20.10:
intel-microcode 3.20210608.0ubuntu0.20.10.1

Ubuntu 20.04 LTS:
intel-microcode 3.20210608.0ubuntu0.20.04.1

Ubuntu 18.04 LTS:
intel-microcode 3.20210608.0ubuntu0.18.04.1

Ubuntu 16.04 ESM:
intel-microcode 3.20210608.0ubuntu0.16.04.1+esm1

Ubuntu 14.04 ESM:
intel-microcode 3.20210608.0ubuntu0.14.04.1+esm1

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

References:
  https://ubuntu.com/security/notices/USN-4985-1
CVE-2020-24511, CVE-2020-24512, CVE-2020-24513, CVE-2021-24489

Package Information:
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20210608.0ubuntu0.21.04.1
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20210608.0ubuntu0.20.10.1
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20210608.0ubuntu0.20.04.1
  https://launchpad.net/ubuntu/+source/intel-microcode/3.20210608.0ubuntu0.18.04.1