RHEL 5 : gdm (RHSA-2013:1213)
Medium Nessus Plugin ID 69795
SynopsisThe remote Red Hat host is missing one or more security updates.
DescriptionUpdated gdm and initscripts packages that fix one security issue are now available for Red Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having important 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.
The GNOME Display Manager (GDM) provides the graphical login screen, shown shortly after boot up, log out, and when user-switching.
A race condition was found in the way GDM handled the X server sockets directory located in the system temporary directory. An unprivileged user could use this flaw to perform a symbolic link attack, giving them write access to any file, allowing them to escalate their privileges to root. (CVE-2013-4169)
Note that this erratum includes an updated initscripts package. To fix CVE-2013-4169, the vulnerable code was removed from GDM and the initscripts package was modified to create the affected directory safely during the system boot process. Therefore, this update will appear on all systems, however systems without GDM installed are not affected by this flaw.
Red Hat would like to thank the researcher with the nickname vladz for reporting this issue.
All users should upgrade to these updated packages, which correct this issue. The system must be rebooted for this update to take effect.
SolutionUpdate the affected packages.