The 'Unusual Web Request' rule leverages machine learning to monitor web requests, identifying rare URLs that may suggest malicious web browsing activity. It operates on the premise that adversaries exploit unusual URLs on trusted websites to facilitate initial access, command-and-control (C2) communication, or data exfiltration. When rare URLs are detected, they can indicate web attacks like watering hole attacks where a compromised legitimate site is used to lure targets. The rule is designed to flag requests for these unusual URLs that deviate from normal user patterns, helping security teams respond proactively to potential threats. False positives can occur from legitimate web activity that is infrequent. Investigative measures include reviewing alert details, checking historical logs, analyzing user agents, and correlating with other security events. This rule is part of a strategic layer of security designed to enhance detection capabilities for potential threats in network and endpoint contexts.