1. Ubuntu Security Notices
  2. USN-3484-2

USN-3484-2: Linux kernel (HWE) vulnerability

Publication date

21 November 2017

Overview

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

Releases

Packages

  • linux-hwe - Linux hardware enablement (HWE) kernel

Details

USN-3484-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.04.
This update provides the corresponding updates for the Linux Hardware
Enablement (HWE) kernel from Ubuntu 17.04 for Ubuntu 16.04 LTS.

It was discovered that the KVM subsystem in the Linux kernel did not
properly keep track of nested levels in guest page tables. A local attacker
in a guest VM could use this to cause a denial of service (host OS crash)
or possibly execute arbitrary code in the host OS.

USN-3484-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.04.
This update provides the corresponding updates for the Linux Hardware
Enablement (HWE) kernel from Ubuntu 17.04 for Ubuntu 16.04 LTS.

It was discovered that the KVM subsystem in the Linux kernel did not
properly keep track of nested levels in guest page tables. A local attacker
in a guest VM could use this to cause a denial of service (host OS crash)
or possibly execute arbitrary code in the host OS.

Update instructions

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

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
16.04 xenial linux-image-4.10.0-40-generic –  4.10.0-40.44~16.04.1
linux-image-4.10.0-40-generic-lpae –  4.10.0-40.44~16.04.1
linux-image-4.10.0-40-lowlatency –  4.10.0-40.44~16.04.1

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References

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