Which of the following is the MOST beneficial to review when performing an IT audit?

Security logs provide a chronological record of events and are the most beneficial source of evidence for an IT auditor. They offer direct, factual data on what has actually occurred on systems and networks, including user activities, system changes, and security events. By analyzing these logs, an auditor can verify whether security controls are operating effectively, whether policies are being complied with, and can identify anomalies or potential security incidents. While policies and configuration settings establish the criteria and state of a system, logs provide the evidence of operational reality, making them the most crucial element for review.

1. (ISC)² CISSP Official Study Guide, 9th Edition. Chapter 13, "Security Assessment and Testing," discusses security audits. It emphasizes that auditors review evidence to determine compliance. The text states, "Auditors often review log files, security settings, and other records to verify that policies are being followed." Logs are presented as a primary form of evidence for what has occurred.

2. NIST Special Publication 800-53A, Revision 5, Assessing Security and Privacy Controls in Information Systems and Organizations. The assessment procedures for the Audit and Accountability (AU) control family, such as AU-2 (Audit Events) and AU-6 (Audit Record Review, Analysis, and Reporting), explicitly list "Examine" as a primary assessment method. This involves reviewing "system audit records" and "audit review, analysis, and reporting documentation" to determine if controls are implemented correctly and are effective. This positions logs (audit records) as the direct evidence to be examined.

3. NIST Special Publication 800-92, Guide to Computer Security Log Management. Section 2.2, "Log Management Operational Processes," states that log analysis is a key component of security auditing and forensics. It highlights that logs are used to "demonstrate compliance with regulations and facilitate security auditing and problem resolution." This underscores the central role of logs as the primary data source for an audit.