Behavioral review is the analysis of what a system, user, or process actually does, rather than relying only on known bad indicators such as hashes, domains, or filenames. It looks for patterns like unusual process chains, privilege changes, unexpected network activity, persistence behavior, or deviations from a normal baseline.
This matters because attackers often change their tools faster than defenders can update signatures. A file may be new and unknown, but its behavior can still reveal reconnaissance, lateral movement, data staging, or command-and-control activity. In defense, behavioral review helps validate whether a host still behaves as trusted after an alert is contained. It is especially useful in cleanup and incident response, where removing one IOC does not prove the environment is safe. By comparing current activity to expected system state, teams can spot hidden compromise that signature matching alone would miss.