Red Hat Security Advisory
Synopsis: Moderate: gdm security update
Advisory ID: RHSA-2011:0395-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2011-0395.html
Issue date: 2011-03-28
CVE Names: CVE-2011-0727
Updated gdm packages that fix one security issue are now available for Red
Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.
2. Relevant releases/architectures:
Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64
Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64
Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64
The GNOME Display Manager (GDM) provides the graphical login screen, shown
shortly after boot up, log out, and when user-switching.
A race condition flaw was found in the way GDM handled the cache
directories used to store users' dmrc and face icon files. A local attacker
could use this flaw to trick GDM into changing the ownership of an
arbitrary file via a symbolic link attack, allowing them to escalate their
Red Hat would like to thank Sebastian Krahmer of the SuSE Security Team for
reporting this issue.
All users should upgrade to these updated packages, which contain a
backported patch to correct this issue. GDM must be restarted for this
update to take effect. Rebooting achieves this, but changing the runlevel
from 5 to 3 and back to 5 also restarts GDM.
Before applying this update, make sure all previously-released errata
relevant to your system have been applied.
This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at