As a developer, you likely rely on GitHub Actions and other CI/CD tools to automate your projects’ builds, tests, and deployments. However, these powerful platforms also present security risks if not configured carefully. Hackers actively target vulnerabilities in automation workflows to infiltrate codebases and supply chains. 

Luckily, with some simple precautions, you can help protect your code and keep your workflows secure. Here are four tips researchers recently uncovered to strengthen your GitHub Actions against common injection attacks: 

1. Avoid Direct Command Substitution

When specifying commands to run in your workflow, be wary of directly interpolating user input like issue titles or pull request bodies. Hackers can craft malicious input to execute arbitrary code on your behalf. 

Instead, assign untrusted values to environment variables first. Then reference those variables securely within your script or run commands. For example, set the title as an env var before using it in a Bash script. This separation prevents unintended command execution. 

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2.   Enable Automated Code Scanning

Mistakes happen, even for experienced developers. Leverage GitHub’s CodeQL scanning to catch vulnerabilities before hackers do. The Security Lab has built queries to find unsafe variable interpolation in workflows. 

Enable scanning for your default languages as well as JavaScript to check workflows. The scans will surface issues over time without disrupting your workflow. Fixing errors proactively is safer than waiting to be exploited. 

3.   Restrict Workflow Permissions 

By default, GitHub Actions tokens have broad access, more than most workflows require. Review and reduce your default permissions to a strict minimum under “Settings > Actions”. 

To exert more precise control, employ the Permission Monitor action to provide each task with just the necessary level of access. This practice of granting the least privilege minimizes the potential impact in case a workflow gets compromised. 

 4.   Enable Private Vulnerability Reporting 

No system is perfectly secure. Establish a channel for researchers to disclose issues via your Settings > Security options confidentially. Private reports allow fixing vulnerabilities discreetly before attackers discover them. 

An open collaboration between developers and researchers strengthens security for all. Implement these best practices to proactively harden your automation and stay one step ahead of threats targeting your code. Let me know if any part of the implementation process remains unclear! 

Conclusion 

GitHub Actions and other CI/CD platforms power incredible development but also introduce new risks to consider. By applying these tips from real-world research, you can help secure your workflows and keep hackers at bay.