USN-3255-1: LightDM vulnerability

Ubuntu Security Notice USN-3255-1

4th April, 2017

lightdm vulnerability

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS

Summary

LightDM could be made to run programs as an administrator.

Software description

  • lightdm - Display Manager

Details

It was discovered that LightDM incorrectly handled home directory creation for
guest users. A local attacker could use this issue to gain ownership of
arbitrary directory paths and possibly gain administrative privileges.

Update instructions

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

Ubuntu 16.10:
lightdm 1.19.5-0ubuntu1.1
Ubuntu 16.04 LTS:
lightdm 1.18.3-0ubuntu1.1

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

In general, a standard system update will make all the necessary changes.

References

CVE-2017-7358