This detection rule identifies user activity originating from IP addresses that are categorized as anonymous proxies. By analyzing sign-in events captured by Azure's risk detection service, the rule filters for instances labeled as 'riskyIPAddress'. The purpose is to flag potential unauthorized access or compromised accounts wherein users might be signing in from locations that obscure their true identity, thus presenting a heightened risk. Given the growing use of various anonymization services by malicious actors, this detection plays an essential role in enhancing the security posture by allowing organizations to investigate unusual sign-in attempts and enforce mitigation measures effectively.