Threat localization is the process of pinpointing where suspicious or malicious activity is happening inside a network, host, or cyber-physical system. It goes beyond simple detection: once an alert exists, defenders still need to find the affected device, subnet, process, user, or control segment.
This matters because response speed depends on accuracy. In enterprise security, localization helps analysts isolate compromised endpoints, trace lateral movement, and reduce the blast radius of ransomware or intrusions. In critical infrastructure such as the electric grid, it can help distinguish a real cyber event from sensor noise, equipment faults, or bad data, which is essential when operators must act quickly. Security tools use logs, telemetry, packet data, and behavioral models to localize threats, but the result must still be checked by humans when the system is safety-critical.