CVE-2014-3421

lisp/gnus/gnus-fun.el in GNU Emacs 24.3 and earlier allows local users to overwrite arbitrary files via a symlink attack on the /tmp/gnus.face.ppm temporary file.

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://advisories.mageia.org/MGASA-2014-0250.html
• http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17428#8
• http://lists.gnu.org/archive/html/emacs-diffs/2014-05/msg00055.html
• http://openwall.com/lists/oss-security/2014/05/07/7
• http://www.mandriva.com/security/advisories?name=MDVSA-2015:117