This detection rule identifies when a GitHub Actions workflow contains a checkout step, which utilizes the 'actions/checkout' to pull repository code into the workflow runner. The primary goal is to enhance security by flagging workflows, especially those triggered by 'pull_request_target' events or workflows with elevated permissions, as checking out untrusted code may lead to vulnerabilities. The rule is designed to monitor such actions within CI/CD pipelines to encourage security review and compliance with best practices. By maintaining awareness of workflows that involve code checkout, organizations can mitigate risks associated with unverified code execution and supply chain attacks.