Ubuntu 20.10 & 20.04 LTS USN-4727-1 Critical Denial Of Service Issue

ubuntu

February 9, 2021

The system could be made to crash or run programs as an administrator.

Summary

The system could be made to crash or run programs as an administrator.

Software Description:

- linux: Linux kernel

- linux-aws: Linux kernel for Amazon Web Services (AWS) systems

- linux-azure: Linux kernel for Microsoft Azure Cloud systems

- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems

- linux-kvm: Linux kernel for cloud environments

- linux-oracle: Linux kernel for Oracle Cloud systems

- linux-raspi: Linux kernel for Raspberry Pi (V8) systems

- linux-hwe-5.8: Linux hardware enablement (HWE) kernel

- linux-oem-5.6: Linux kernel for OEM systems

Details:

Alexander Popov discovered that multiple race conditions existed in the

AF_VSOCK implementation in the Linux kernel. A local attacker could use

this to cause a denial of service (system crash) or execute arbitrary code.

Topics Covered

security advisory denial of service critical issue security issue Ubuntu kernel ubuntu system crash administrative access

Update Instructions

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

Ubuntu 20.10:
  linux-image-5.8.0-1015-raspi    5.8.0-1015.18
  linux-image-5.8.0-1015-raspi-nolpae  5.8.0-1015.18
  linux-image-5.8.0-1018-kvm      5.8.0-1018.20
  linux-image-5.8.0-1020-oracle   5.8.0-1020.21
  linux-image-5.8.0-1022-azure    5.8.0-1022.24
  linux-image-5.8.0-1022-gcp      5.8.0-1022.23
  linux-image-5.8.0-1023-aws      5.8.0-1023.25
  linux-image-5.8.0-43-generic    5.8.0-43.49
  linux-image-5.8.0-43-generic-64k  5.8.0-43.49
  linux-image-5.8.0-43-generic-lpae  5.8.0-43.49
  linux-image-5.8.0-43-lowlatency  5.8.0-43.49
  linux-image-aws                 5.8.0.1023.25
  linux-image-azure               5.8.0.1022.22
  linux-image-gcp                 5.8.0.1022.22
  linux-image-generic             5.8.0.43.48
  linux-image-generic-64k         5.8.0.43.48
  linux-image-generic-lpae        5.8.0.43.48
  linux-image-gke                 5.8.0.1022.22
  linux-image-kvm                 5.8.0.1018.20
  linux-image-lowlatency          5.8.0.43.48
  linux-image-oracle              5.8.0.1020.19
  linux-image-raspi               5.8.0.1015.18
  linux-image-raspi-nolpae        5.8.0.1015.18
  linux-image-virtual             5.8.0.43.48

Ubuntu 20.04 LTS:
  linux-image-5.6.0-1047-oem      5.6.0-1047.51
  linux-image-5.8.0-43-generic    5.8.0-43.49~20.04.1
  linux-image-5.8.0-43-generic-lpae  5.8.0-43.49~20.04.1
  linux-image-5.8.0-43-lowlatency  5.8.0-43.49~20.04.1
  linux-image-generic-64k-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-generic-hwe-20.04   5.8.0.43.49~20.04.29
  linux-image-generic-lpae-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-lowlatency-hwe-20.04  5.8.0.43.49~20.04.29
  linux-image-oem-20.04           5.6.0.1047.43
  linux-image-virtual-hwe-20.04   5.8.0.43.49~20.04.29

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.