USN-4096-1: Linux kernel (AWS) vulnerability

13 August 2019

linux-aws, linux-aws-hwe vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 19.04
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS

Summary

The system could be made to expose sensitive information.

Software Description

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

Details

Andrei Vlad Lutas and Dan Lutas discovered that some x86 processors incorrectly handle SWAPGS instructions during speculative execution. A local attacker could use this to expose sensitive information (kernel memory).

Update instructions

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

Ubuntu 19.04
linux-image-5.0.0-1012-aws - 5.0.0-1012.13
linux-image-aws - 5.0.0.1012.12
Ubuntu 18.04 LTS
linux-image-4.15.0-1045-aws - 4.15.0-1045.47
linux-image-aws - 4.15.0.1045.44
Ubuntu 16.04 LTS
linux-image-4.15.0-1045-aws - 4.15.0-1045.47~16.04.1
linux-image-aws-hwe - 4.15.0.1045.45

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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