Ubuntu 16.10 / 17.04 : lightdm vulnerability (USN-3285-1)
Low Nessus Plugin ID 100156
SynopsisThe remote Ubuntu host is missing a security-related patch.
DescriptionTyler 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.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected lightdm package.