CVE-2015-3627

Libcontainer and Docker Engine before 1.6.1 opens the file-descriptor passed to the pid-1 process before performing the chroot, which allows local users to gain privileges via a symlink attack in an image.

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