USN-3285-1: LightDM vulnerability
Ubuntu Security Notice USN-3285-1
11th May, 2017
lightdm vulnerability
A security issue affects these releases of Ubuntu and its
derivatives:
- Ubuntu 17.04
- Ubuntu 16.10
Summary
LightDM could allow unintended access to files.
Software description
- lightdm
– Display Manager
Details
Tyler Hicks discovered that LightDM did not confine the user session for guest
users. An attacker with physical access could use this issue to access files
and other resources that they should not be able to access. In the default
installation, this includes files in the home directories of other users on the
system. This update fixes the issue by disabling the guest session. It may be
re-enabled in a future update. Please see the bug referenced below for
instructions on how to manually re-enable the guest session.
Update instructions
The problem can be corrected by updating your system to the following
package version:
- Ubuntu 17.04:
-
lightdm
1.22.0-0ubuntu2.1
- Ubuntu 16.10:
-
lightdm
1.19.5-0ubuntu1.2
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.
References
Source: USN-3285-1: LightDM vulnerability
