CVE-2014-1624

Race condition in the xdg.BaseDirectory.get_runtime_dir function in python-xdg 0.25 allows local users to overwrite arbitrary files by pre-creating /tmp/pyxdg-runtime-dir-fallback-victim to point to a victim-owned location, then replacing it with a symlink to an attacker-controlled location once the get_runtime_dir function is called.

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://bugs.debian.org/cgi-bin/bugreport.cgi?bug=736247
• http://www.openwall.com/lists/oss-security/2014/01/21/3
• http://www.openwall.com/lists/oss-security/2014/01/21/4
• http://www.securityfocus.com/bid/65042
• https://exchange.xforce.ibmcloud.com/vulnerabilities/90618