What is the difference between event logging and audit trails in OT security?

• A. Event logs capture operational events; audit trails record actions for compliance and forensic analysis and are tamper-evident
• B. Event logs are tamper-evident; audit trails are used for performance metrics
• C. Event logs are the same as audit trails
• D. Audit trails only record login events

Answer: (A)

In OT security, you’re looking at two related but distinct ways to record what happens in the system. Event logging captures regular operational events from devices and software—things like state changes, alarms, or routine messages—so engineers can monitor, troubleshoot, and understand how the system is behaving. Audit trails, on the other hand, are built to provide traceability for accountability, regulatory compliance, and forensic analysis. They record who did what, when, and often where, and they’re designed to be tamper-evident so that any attempted alteration is detectable.

The best choice matches this difference: event logs document operational events, while audit trails focus on recording actions for compliance and forensic purposes and include tamper-evident protections to preserve integrity. This distinction is important because it explains why one type supports troubleshooting and performance monitoring, while the other supports accountability and investigations.

Other options aren’t accurate because:

• Audit trails are not just for performance metrics; their primary role is accountability and forensic integrity, not routine performance data.

• Event logs and audit trails are not the same thing; they serve different purposes and have different requirements (especially regarding tamper resistance).

• Audit trails aren’t limited to recording login events; they track a wider range of actions to establish a complete sequence of events for later review.