USN-3285-1: LightDM vulnerability
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of USN-3285-1?
The severity of USN-3285-1 is considered important due to the risk of unauthorized access to user files.
How do I fix USN-3285-1?
To fix USN-3285-1, ensure you update the LightDM package to versions 1.22.0-0ubuntu2.1 or 1.19.5-0ubuntu1.2, depending on your Ubuntu release.
Which Ubuntu versions are affected by USN-3285-1?
USN-3285-1 affects Ubuntu versions 17.04 and 16.10 that use vulnerable versions of LightDM.
Who discovered the vulnerability in USN-3285-1?
The vulnerability in USN-3285-1 was discovered by security researcher Tyler Hicks.
What potential risk does USN-3285-1 pose?
USN-3285-1 poses a risk that an attacker with physical access could gain unauthorized access to sensitive files and resources.