Intrusion simulation is a controlled exercise that tests how a system, team, or security control behaves during an attack path. Unlike a simple vulnerability scan, it tries to model how an intruder could move from initial access to later stages such as privilege escalation, lateral movement, and domain compromise.
This matters because many real attacks succeed through chains of small weaknesses rather than one dramatic flaw. Security teams use intrusion simulations to evaluate segmentation, identity controls, logging, alerting, and incident response under realistic pressure. In defense work, they can reveal whether one blocked step stops the whole path or whether an attacker could keep advancing through exposed services, weak credentials, or misconfigurations. A good simulation helps blue teams find broken assumptions before an actual adversary does.