CVE-2015-3629

Libcontainer 1.6.0, as used in Docker Engine, allows local users to escape containerization (mount namespace breakout) and write to arbitrary file on the host system via a symlink attack in an image when respawning a container.

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://lists.opensuse.org/opensuse-updates/2015-05/msg00023.html
• http://packetstormsecurity.com/files/131835/Docker-Privilege-Escalation-Information-Disclosure.html
• http://seclists.org/fulldisclosure/2015/May/28
• http://www.securityfocus.com/bid/74558
• https://groups.google.com/forum/#%21searchin/docker-user/1.6.1/docker-user/47GZrihtr-4/nwgeOOFLexIJ