auditinglogging

Auditing and logging refer to the collection, examination, and retention of records that document the activities and events within information systems. Logging is the ongoing process of recording discrete events such as user actions, system changes, access attempts, and errors. Auditing is the targeted evaluation of these records to verify compliance, detect unauthorized activity, and support investigations. Together they create an audit trail that enables accountability and traceability.

Log sources include operating systems, applications, databases, network devices, and cloud services. Log data typically includes timestamps, user identifiers, actions taken, resource names, outcomes, and context. Effective auditing requires tamper-evident storage, data integrity checks, and time synchronization.

Common goals include incident response, forensics, regulatory compliance, access control validation, and performance monitoring. A well-designed program distinguishes between raw logs and analyzed audit records, implements retention and privacy controls, and uses centralized collection to enable correlation across systems.

Implementation best practices: define a written logging and auditing policy; collect only necessary data and redact sensitive information where possible; protect logs with access controls and tamper-resistant storage; transport logs securely (for example, TLS); normalize and index data for searchability; retain logs for legally mandated periods; monitor with alerting and a security information and event management (SIEM) system; perform regular reviews and audits; ensure clock integrity with NTP.

Standards and regulatory considerations include ISO/IEC 27001, PCI DSS, HIPAA, SOC 2, and GDPR/privacy requirements that mandate audit trails and data retention.

Challenges include high data volume, noise, privacy constraints, log integrity, time synchronization, and cross-domain correlation. Examples include database audit trails, application logs, system and security logs, and file integrity monitoring.