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Ubuntu 18.04 LTS USN-5071-2 Critical: Kernel Security Issues Addressed

ubuntu
Calendar Grey September 16, 2021
Dist Ubuntu Esm H88
Recent security patches for the Linux kernel in Ubuntu 20.04 LTS address severe vulnerabilities, with detailed update instructions included.
Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux-hwe-5.4: Linux hardware enablement (HWE) kernel

Details:

USN-5071-1 fixed vulnerabilities in the Linux kernel for Ubuntu 20.04

LTS. This update provides the corresponding updates for the Linux

Hardware Enablement (HWE) kernel from Ubuntu 20.04 LTS for Ubuntu

18.04 LTS.

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor

implementation for AMD processors in the Linux kernel allowed a guest VM to

disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a

guest VM could use this to read or write portions of the host's physical

memory. (CVE-2021-3656)

Maxim Levitsky discovered that the KVM hypervisor implementation for AMD

processors in the Linux kernel did not properly prevent a guest VM from

enabling AVIC in nested guest VMs. An attacker in a guest VM could use this

to write to portions of the host's physical memory. (CVE-2021-3653)

It was discovered that the KVM...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory DoS kernel system update ubuntu hypervisor

Update Instructions

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

Ubuntu 18.04 LTS:
  linux-image-5.4.0-84-generic    5.4.0-84.94~18.04.1
  linux-image-5.4.0-84-generic-lpae  5.4.0-84.94~18.04.1
  linux-image-5.4.0-84-lowlatency  5.4.0-84.94~18.04.1
  linux-image-generic-hwe-18.04   5.4.0.84.94~18.04.75
  linux-image-generic-lpae-hwe-18.04  5.4.0.84.94~18.04.75
  linux-image-lowlatency-hwe-18.04  5.4.0.84.94~18.04.75
  linux-image-oem                 5.4.0.84.94~18.04.75
  linux-image-oem-osp1            5.4.0.84.94~18.04.75
  linux-image-snapdragon-hwe-18.04  5.4.0.84.94~18.04.75
  linux-image-virtual-hwe-18.04   5.4.0.84.94~18.04.75

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

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References

https://ubuntu.com/security/notices/USN-5071-2

https://ubuntu.com/security/notices/USN-5071-1

CVE-2020-36311, CVE-2021-22543, CVE-2021-3612, CVE-2021-3653,

CVE-2021-3656

Severity
critical
Lowest
Low
Medium
High
Critical

September 16, 2021

Topics%20covered

Topics Covered

security advisory DoS kernel system update ubuntu hypervisor

Package Information

https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-84.94~18.04.1

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