Personam has developed a new approach to detecting insider threats on computer networks using machine learning techniques. The approach involves placing sensors throughout the network to observe all data transfers and build rich behavioral profiles of all actors, including employees, contractors, devices and processes. It analyzes the behavioral profiles to identify similarities between actors and group them into cohorts matching the organization's structure. The system monitors for deviations from individual profiles and differences from an actor's cohort that could indicate threatening activity. This advanced approach can identify insider threats even if they are hiding malicious actions within normal behavior patterns.