Critical Events to Monitor

Effective security monitoring starts with identifying what events matter. Authentication events top the list: failed login attempts, successful logins from new locations or devices, password changes, and privilege escalations all warrant logging. It's like noting everyone who enters and exits a building, especially those who try doors they shouldn't access.

Access control failures deserve particular attention. Log every attempt to access resources without proper authorization, whether it's trying to view another user's data or accessing administrative functions. These events often indicate either attacks in progress or misconfigurations that need correction. High-value transactions—money transfers, data exports, configuration changes—should generate detailed audit trails. Input validation failures, while common, can indicate attempted SQL injection or XSS attacks when they occur in patterns.