An issue has been discovered in the Cloud Native Computing Foundation (CNCF) Helm versions up to 3.13.3, where running a --dry-run would display values for secrets. This might cause security concerns, particularly in use cases where a CI/CD tool performs a dry-run and the output becomes visible to unauthorized personnel.

Here's an example of a Helm command that would trigger the issue

helm install my-release --debug --dry-run --values=my-secrets.yaml my-chart/

If my-secrets.yaml contains sensitive information and the dry-run output is visible in an insecure location, this could lead to possible data being compromised.

The report for this issue can be found on the public CVE database here

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-25210

The official GitHub issue can be found here

https://github.com/helm/helm/issues/8149

Exploit Details

The primary exploitation scenario is when the vulnerable Helm version is used by a CI/CD tool that is configured to do a dry-run with secret values. In such a scenario, the output of the CI/CD tool, including secrets, might be visible to unauthorized persons.

Unfortunately, this behavior was intentionally introduced as an enhancement, and the project team has acknowledged the immpossibility of removing it without breaking backwards compatibility for some users who rely on this feature. Hence, it is essential for users to be cautious when using this feature in their CI/CD tools or other environments that may expose output to unauthorized users.

Vendor's Position

The Helm Project team believes it is not their responsibility to safeguard users who decide to use the --dry-run flag in their CI/CD environments. They urge users to be cautious while using this feature and ensure that the output of a dry-run is not visible in any insecure environments.

Mitigations

1. Avoid using the --dry-run flag in CI/CD environments or other insecure setups if it can potentially expose secret values.
2. Ensure that the output of your CI/CD tool is secured from unauthorized access.
3. Review the security policies and user access control within your environment to minimize the risks from this behavior.

In conclusion, while the Helm Project team does not consider the behavior to be a vulnerability on their end, there are still potential security risks and possible mitigation strategies that users should implement on their side to ensure the secure use of Helm and their CI/CD tools.

Timeline

Published on: 03/03/2024 21:15:49 UTC
Last modified on: 09/04/2024 18:35:00 UTC