1. Ubuntu Security Notices
  2. USN-3234-2

USN-3234-2: Linux kernel (Xenial HWE) vulnerabilities

Publication date

15 March 2017

Overview

Several security issues were fixed in the kernel.

Releases

Packages

Details

USN-3234-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu
14.04 LTS.

Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel
did not properly validate meta block groups. An attacker with physical
access could use this to specially craft an ext4 image that causes a denial
of service (system crash). (CVE-2016-10208)

It was discovered that the Linux kernel did not clear the setgid bit during
a setxattr call on a tmpfs filesystem. A local attacker could use this to
gain elevated group privileges. (CVE-2017-5551)

USN-3234-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu
14.04 LTS.

Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel
did not properly validate meta block groups. An attacker with physical
access could use this to specially craft an ext4 image that causes a denial
of service (system crash). (CVE-2016-10208)

It was discovered that the Linux kernel did not clear the setgid bit during
a setxattr call on a tmpfs filesystem. A local attacker could use this to
gain elevated group privileges. (CVE-2017-5551)

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
14.04 trusty linux-image-4.4.0-67-generic –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-generic-lpae –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-lowlatency –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-powerpc-e500mc –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-powerpc-smp –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-powerpc64-emb –  4.4.0-67.88~14.04.1
linux-image-4.4.0-67-powerpc64-smp –  4.4.0-67.88~14.04.1

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Get Ubuntu Pro

References

Have additional questions?

Talk to a member of the team ›