Authored by Jesse Houwing, this detailed post focuses on safeguarding GitHub Action repositories, outlining practical recommendations to counteract risks like those recently exposed in the changed-files hack.

Protect the Repository Hosting Your GitHub Action

Author: Jesse Houwing

This post, now 2 years old, is still very valid, especially in light of the changed-files hack recently.

Introduction

If you maintain or author GitHub Actions, it’s vital to ensure the security of the repository that hosts your Action. With recent security incidents, such as the changed-files hack, it’s clear that taking a proactive stance on repository security is more important than ever.

Key Recommendations

1. Strengthen Repository Protection

  • Control Access: Limit who can push or merge changes, especially to important branches like main or master.
  • Branch Protection Rules: Enforce status checks, required reviews, and prevent force-pushes and deletions on critical branches.
  • Dependabot Alerts: Enable and monitor security alerts to detect and address vulnerabilities early.

2. Token Security

  • Restricted Token Scopes: Ensure CI/CD tokens (such as GITHUB_TOKEN) only have the minimal permissions your workflow actually needs.
  • Minimize Token Leakage: Audit logs and secrets for accidental exposure of session or personal access tokens. If a token is leaked, rotate it immediately and assess possible impact.

3. Versioning Weaknesses and Developments

  • The standard approach of using tags and branches for versioning GitHub Actions is weak and can be exploited if someone compromises references.
  • There are ongoing discussions and rumors of GitHub moving the distribution of Actions to more robust models, such as the GitHub Container Registry. While this approach presents improvements, it is not yet the default standard.

Practical Guidance

  • Review your repository’s permissions and protection settings regularly.
  • Monitor for abnormal or unexpected changes, particularly when workflows or automation are used.
  • Stay up-to-date with GitHub’s evolving recommendations for securing Actions and workflows.

Conclusion

These recommendations, although originally written two years ago, are still pertinent in today’s evolving security landscape. Being vigilant and implementing strong controls over your Action repositories will help ensure the integrity and security of your automation pipelines.

For further details and a deeper dive into securing your GitHub Action repositories, visit Jesse Houwing’s original post.

This post appeared first on “Jesse Houwing’s Blog”. Read the entire article here