Manual log analysis is the human review of security logs to understand what systems, controls, or users are doing. Analysts inspect events such as firewall records, authentication logs, proxy traces, or cloud audit trails and then infer whether a rule matched traffic, a service was accessed, or an action was blocked.
It matters because logs often contain the only evidence of how a control behaves in practice. In defense, teams use manual review to validate alerts, spot policy drift, and discover unused rules or misconfigurations when automated summaries are missing or incomplete. In attacks, defenders may manually correlate logs to reconstruct intrusion paths, identify suspicious sequences, or confirm lateral movement. The method is flexible, but it is slow, error-prone at scale, and depends on good log coverage and retention.