Counter-surveillance is the practice of detecting secret monitoring before it can be used against you. In cyber security, it covers more than software scanning: it includes checking rooms, vehicles, devices, and networks for hidden cameras, microphones, trackers, or other observation tools. The goal is to spot surveillance early so an attacker cannot collect video, audio, credentials, or movement patterns unnoticed.
It matters because many attacks rely on stealth rather than force. A hidden camera in a charger, a rogue Wi‑Fi probe, or a planted Bluetooth tracker can expose private behavior and sensitive work. Counter-surveillance tools use visual inspection, RF detection, infrared checks, and optical methods that look for lens reflections or unusual signals. Used well, they are a screening layer that reduces risk, but they must be paired with careful judgment because false positives are common.