CVE-2011-4028

The LockServer function in os/utils.c in X.Org xserver before 1.11.2 allows local users to determine the existence of arbitrary files via a symlink attack on a temporary lock file, which is handled differently if the file exists.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• http://cgit.freedesktop.org/xorg/xserver/commit/?id=6ba44b91e37622ef8c146d8f2ac92d708a18ed34
• http://lists.freedesktop.org/archives/xorg/2011-October/053680.html
• http://rhn.redhat.com/errata/RHSA-2012-0939.html
• http://secunia.com/advisories/46460
• http://secunia.com/advisories/49579