The detection rule identifies unauthorized HTTP method usage in web applications, as indicated by HTTP 405 (Method Not Allowed) responses. HTTP methods are crucial for defining the type of action requested from a web resource, such as GET, POST, or DELETE. When a web application receives a request using an unsupported method, it returns a 405 status code, signaling potential misuse or probing efforts by adversaries. The rule leverages logs indexed by APM transaction data to flag such instances, allowing for the identification of suspicious activities that may exploit misconfigurations or vulnerabilities in the application. False positives are possible, stemming from security scans, misconfigured applications, or routine use of unsupported methods in testing environments. The rule provides a guide for triage, investigation steps, and response actions, including reviewing logs, blocking malicious IPs, and assessing application configurations to enhance security controls against unauthorized access attempts.