During which operational phase is an intrusion detection system (IDS) activated when a sensor reacts to external stimuli?

An intrusion detection system (IDS) is activated during the detection phase. This is the phase where the system first identifies potential security breaches through various sensors that respond to external stimuli, such as unauthorized access attempts or other suspicious activities. These sensors may include motion detectors, door/window contacts, and video surveillance systems. When they sense an anomaly, they trigger an alert, indicating that a potential intrusion is occurring.

This phase is crucial for early identification of security threats, allowing organizations to act swiftly to mitigate risks. Following the detection phase, other phases such as response or alarm may come into play, but the initial activation of the IDS directly correlates with the detection of an incident.