USN-1262-1: Light Display Manager vulnerabilities

Ubuntu Security Notice USN-1262-1

15th November, 2011

lightdm vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 11.10

Summary

Several security issues were fixed in Light Display Manager.

Software description

  • lightdm - Display Manager

Details

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.
(CVE-2011-3153)

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)

Update instructions

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.

References

CVE-2011-3153, CVE-2011-4105