The detection rule identifies instances where an anti-phishing policy is deleted within a Microsoft 365 environment. This is crucial because anti-phishing policies are designed to enhance the detection and prevention of phishing attacks, and their removal could expose users to increased risks. The rule operates by monitoring audit logs for specific deletion actions—essentially recording whenever the 'Remove-AntiPhishPolicy' command is executed successfully. This behavior can be indicative of malicious activity aimed at weakening organizational security. The rule provides detailed investigation and response steps, emphasizing the review of audit logs, checking for unauthorized access, evaluating the implications of the policy deletion, and collaborating with IT security teams to ascertain whether the deletion was legitimately authorized or not.