Ubuntu Security Notice USN-1262-1
15th November, 2011
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 11.10
Several security issues were fixed in Light Display Manager.
- lightdm - Display Manager
It was discovered that Light Display Manager incorrectly handled privileges
when reading .dmrc files. A local attacker could exploit this issue to read
arbitrary configuration files, bypassing intended permissions.
It was discovered that Light Display Manager incorrectly handled links when
adjusting permissions on .Xauthority files. A local attacker could exploit
this issue to access arbitrary files, and possibly obtain increased
privileges. In the default Ubuntu installation, this would be prevented
by the Yama link restrictions. (CVE-2011-4105)
The problem can be corrected by updating your system to the following package version:
- Ubuntu 11.10:
- liblightdm-gobject-1-0 1.0.6-0ubuntu1.1
- liblightdm-qt-1-0 1.0.6-0ubuntu1.1
- lightdm 1.0.6-0ubuntu1.1
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.