CVE-2019-18658

In Helm 2.x before 2.15.2, commands that deal with loading a chart as a directory or packaging a chart provide an opportunity for a maliciously designed chart to include sensitive content such as /etc/passwd, or to execute a denial of service (DoS) via a special file such as /dev/urandom, via symlinks. No version of Tiller is known to be impacted. This is a client-only issue.

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

• https://helm.sh/blog/2019-10-30-helm-symlink-security-notice/