A file existence disclosure flaw was found in the way X.Org X11 X server performed management of temporary lock files. A local, unprivileged user could use this flaw to confirm (non) existence of a file system object (file, directory or fifo), which shouldn't be accessible for them, via symbolic link attacks, with link name being the expected name of the X.Org X11 X server temporary lock file. Note: For the exploit to succeed the local attacker needs to be able to run the X.Org X11 X server.
Acknowledgements: Red Hat would like to thank researcher with a nickname vladz for reporting this issue.
Created attachment 528780 [details] Proposed X.Org X11 server upstream patch
This issue is now public. The following commit corrects the problem upstream: http://cgit.freedesktop.org/xorg/xserver/commit/?id=6ba44b91e37622ef8c146d8f2ac92d708a18ed34 External References: http://lists.freedesktop.org/archives/xorg-announce/2011-October/001744.html
Statement: (none)
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2012:0303 https://rhn.redhat.com/errata/RHSA-2012-0303.html
This issue affects the current version (xorg-x11-server-Xorg-1.10.4-1.fc15.*) of the xorg-x11-server package, as shipped with Fedora release of 15. Please schedule an update. -- This issue does NOT affect the current version (xorg-x11-server-Xorg-1.11.4-1.fc16) of the xorg-x11-server package, as shipped with Fedora release of 16. The deficiency in this version is corrected already.
Created xorg-x11-server tracking bugs for this issue Affects: fedora-15 [bug 799349]
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2012:0939 https://rhn.redhat.com/errata/RHSA-2012-0939.html