USN-2645-1: Linux kernel (Vivid HWE) vulnerability

15 June 2015

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

Philip Pettersson discovered a privilege escalation when using overlayfs mounts inside of user namespaces. A local user could exploit this flaw to gain administrative privileges on the system.

Update instructions

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

Ubuntu 14.04 LTS
linux-image-3.19.0-21-generic - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-generic-lpae - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-lowlatency - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-powerpc-e500mc - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-powerpc-smp - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-powerpc64-emb - 3.19.0-21.21~14.04.1
linux-image-3.19.0-21-powerpc64-smp - 3.19.0-21.21~14.04.1

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. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.

References