The concept of security logging has its roots in early operating systems of the 1960s, where command histories were preserved for debugging and accountability. As computer networks expanded and cyber threats evolved, security logs became a foundational component of Information Security Management Systems (ISMS) and compliance frameworks such as ISO/IEC 27001, NIST SP 800-92, and the General Data Protection Regulation (GDPR). Modern security information and event management (SIEM) solutions aggregate and analyze logs from diverse sources, enabling correlated event detection and automated alerting.
Typical security logs include authentication logs, application logs, firewall and router logs, intrusion detection system (IDS) logs, and audit logs from database and virtualization platforms. Each contains fields like timestamp, source IP, destination IP, event type, user identity, and outcome (success or failure). Log integrity is protected through cryptographic hashes, append-only storage, and sometimes secure remote transmission using TLS. Log retention policies vary by industry but must align with legal and regulatory mandates, balancing the need for forensic evidence against storage costs and privacy concerns.
Effective use of a security log involves proper configuration, regular review, and integration with incident response procedures. Analysts employ log correlation, anomaly detection, and machine learning to identify patterns indicative of intrusion or misconfiguration. When logs are incomplete, tampered with, or inadequately stored, organizations risk missing early warning signs of breaches, which can lead to data loss, regulatory fines, and reputational harm.