The Azure Resource Lock Deleted rule is designed to monitor the deletion of resource locks within Azure environments, which serve as protective measures against unauthorized deletions of critical resources such as storage accounts and backups. The rule is particularly significant because ransomware operators, like Storm-0501, often delete these locks to enable deletion of essential data and services, which is a critical precursor to ransomware attacks. This detection rule logs activity categorized under 'Azure.MonitorActivity' and carries a 'High' severity level, underscoring the importance of recognizing such deletions. The rule functions by querying Azure Monitor Activity logs and analyzing patterns of lock deletions, followed by destructive operations that may indicate a ransomware attack. Comprehensive investigation steps are outlined in the runbook, including examining logs for past lock deletion activities, searching for subsequent destructive actions from the same identity, and reviewing previous authentication events for potential signs of credential compromise. The MITRE ATT&CK framework ties the detection to several techniques, such as evading defenses and mishandling recovery measures, making it an essential rule for security posture in cloud environments. Overall, this rule acts as an advance warning system, enabling organizations to react swiftly and mitigate potential ransomware impacts if resource locks are deleted.