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AUSCERT External Security Bulletin Redistribution
12 May 2017
AusCERT Security Bulletin Summary
Operating System: Ubuntu
Impact/Access: Unauthorised Access -- Console/Physical
CVE Names: CVE-2017-8900
Comment: This advisory references vulnerabilities in products which run on
platforms other than Ubuntu. It is recommended that administrators
running lightdm check for an updated version of the software for
their operating system.
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Ubuntu Security Notice USN-3285-1
May 12, 2017
A security issue affects these releases of Ubuntu and its derivatives:
- - Ubuntu 17.04
- - Ubuntu 16.10
LightDM could allow unintended access to files.
- - lightdm: Display Manager
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.
The problem can be corrected by updating your system to the following
After a standard system update you need to reboot your computer to make
all the necessary changes.
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