Building Effective Logging Systems

Effective logging requires more than just writing events to files. Structure logs in consistent, machine-readable formats like JSON to enable automated analysis. Include sufficient context in each log entry: timestamp, user identifier, session ID, source IP, user agent, and the specific action attempted. It's like writing detailed police reports rather than just noting "something happened."

Centralize logs from all application components, servers, and security devices into a security information and event management (SIEM) system or log aggregation platform. Distributed applications might generate logs across dozens of servers—without centralization, correlating events becomes impossible. Protect logs from tampering by storing them on separate systems with restricted access. Attackers often attempt to cover their tracks by deleting or modifying logs. Use write-once storage or cryptographic signatures to ensure log integrity.