The GitHub `pull_request_target` workflows can lead to privilege escalation risks as they run in the context of the target repository, allowing access to secrets and resources not available to regular pull requests. This rule aims to detect usage of such workflows, particularly when triggered by external PRs from forks, which could potentially lead to malicious code execution and unintended access to sensitive data. Non-cross-fork PRs are considered lower risk, but a thorough review is still beneficial. The rule provides a comprehensive runbook that emphasizes the necessity of validating the intention behind the workflows, ensuring they do not execute untrusted code, and implementing security best practices like permission minimization and input validation. Monitoring for unusual activity from external contributors is strongly advised. The rule references the GitHub documentation for further guidelines on the use of workflows.