Ubuntu 18.04 LTS: USN-4426-1 Critical: Kernel Code Execution Risks

ubuntu

July 22, 2020

Several security issues were fixed in the Linux kernel.

Summary

Several security issues were fixed in the Linux kernel.

Software Description:

- linux: Linux kernel

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

- linux-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems

- linux-gke-4.15: Linux kernel for Google Container Engine (GKE) systems

- linux-kvm: Linux kernel for cloud environments

- linux-oem: Linux kernel for OEM systems

- linux-oracle: Linux kernel for Oracle Cloud systems

- linux-raspi2: Linux kernel for Raspberry Pi (V7) systems

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

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

Details:

Jason A. Donenfeld discovered that the ACPI implementation in the Linux

kernel did not properly restrict loading SSDT code from an EFI variable. A

privileged attacker could use this to bypass Secure Boot lockdown

restrictions and execute arbitrary code in the kernel. (CVE-2019-20908)

Fan Yang discovered that the mremap implementati...

Read the Full Advisory

Topics Covered

security advisory denial of service update privilege escalation arbitrary code execution Ubuntu kernel

Update Instructions

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

Ubuntu 18.04 LTS:
  linux-image-4.15.0-1050-oracle  4.15.0-1050.54
  linux-image-4.15.0-1066-gke     4.15.0-1066.69
  linux-image-4.15.0-1067-raspi2  4.15.0-1067.71
  linux-image-4.15.0-1071-kvm     4.15.0-1071.72
  linux-image-4.15.0-1079-aws     4.15.0-1079.83
  linux-image-4.15.0-1080-gcp     4.15.0-1080.90
  linux-image-4.15.0-1093-oem     4.15.0-1093.103
  linux-image-4.15.0-112-generic  4.15.0-112.113
  linux-image-4.15.0-112-generic-lpae  4.15.0-112.113
  linux-image-4.15.0-112-lowlatency  4.15.0-112.113
  linux-image-aws-lts-18.04       4.15.0.1079.81
  linux-image-gcp-lts-18.04       4.15.0.1080.96
  linux-image-generic             4.15.0.112.100
  linux-image-generic-lpae        4.15.0.112.100
  linux-image-gke                 4.15.0.1066.68
  linux-image-gke-4.15            4.15.0.1066.68
  linux-image-kvm                 4.15.0.1071.67
  linux-image-lowlatency          4.15.0.112.100
  linux-image-oem                 4.15.0.1093.96
  linux-image-oracle-lts-18.04    4.15.0.1050.59
  linux-image-powerpc-e500mc      4.15.0.112.100
  linux-image-powerpc-smp         4.15.0.112.100
  linux-image-powerpc64-emb       4.15.0.112.100
  linux-image-powerpc64-smp       4.15.0.112.100
  linux-image-raspi2              4.15.0.1067.65
  linux-image-virtual             4.15.0.112.100

Ubuntu 16.04 LTS:
  linux-image-4.15.0-1050-oracle  4.15.0-1050.54~16.04.1
  linux-image-4.15.0-1079-aws     4.15.0-1079.83~16.04.1
  linux-image-4.15.0-1080-gcp     4.15.0-1080.90~16.04.1
  linux-image-aws-hwe             4.15.0.1079.76
  linux-image-gcp                 4.15.0.1080.82
  linux-image-gke                 4.15.0.1080.82
  linux-image-oracle              4.15.0.1050.41

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.