What is Detect Function?

The Detect function recognizes that preventive controls alone cannot stop all cybersecurity incidents, making timely detection essential for limiting impact. Key categories include anomalies and events (establishing baselines of normal activity and detecting deviations), security continuous monitoring (monitoring information systems and assets for cybersecurity events), and detection processes (maintaining and testing detection processes and procedures). Effective detection requires multiple layers: network monitoring for unusual traffic patterns, endpoint detection and response (EDR) for host-based threats, Security Information and Event Management (SIEM) systems for correlating events across sources, user and entity behavior analytics (UEBA) for insider threats, and cloud security monitoring for infrastructure-level anomalies. The mean time to detect (MTTD) is a critical metric — industry averages show that organizations take 197 days to identify a breach, during which attackers can exfiltrate significant amounts of data. Organizations at higher NIST implementation tiers implement automated detection with machine learning, integrate threat intelligence feeds, conduct regular detection efficacy testing, and maintain documented escalation procedures to ensure detected events receive appropriate attention.