USN-2857-2: Linux kernel (Vivid HWE) vulnerability

5 January 2016

linux-lts-vivid vulnerability

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

  • Ubuntu 14.04 LTS

Summary

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

Software Description

  • linux-lts-vivid - Linux hardware enablement kernel from Vivid

Details

Nathan Williams discovered that overlayfs in the Linux kernel incorrectly handled setattr operations. A local unprivileged attacker could use this to create files with administrative permission attributes and execute arbitrary code with elevated privileges.

Update instructions

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

Ubuntu 14.04 LTS
linux-image-3.19.0-43-generic - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-generic-lpae - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-lowlatency - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-powerpc-e500mc - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-powerpc-smp - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-powerpc64-emb - 3.19.0-43.49~14.04.1
linux-image-3.19.0-43-powerpc64-smp - 3.19.0-43.49~14.04.1

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