The 'Account Lockout' detection rule identifies instances where user accounts are locked due to repeated unsuccessful login attempts, specifically sign-ins that exceed the permissible number of failures, leading to an account being disabled. This is a common indicator of credential stuffing or brute-force attacks, where an attacker systematically tries to guess passwords to gain unauthorized access. By monitoring the Azure Sign-In Logs for events featuring a ResultType of 50053, which corresponds to an account lockout event, this rule assists security teams in detecting potentially malicious activity and protecting against unauthorized access attempts. Proper configuration of alerts based on this rule can help in early detection and rapid response to security incidents involving compromised accounts.