An IoT sensor is a connected device that measures a physical condition such as temperature, humidity, motion, pressure, or location and sends that data to another system. In practice, it turns the physical world into telemetry that software can store, analyze, and act on. In a supply chain, for example, sensors can help verify that goods stayed within safe conditions during transport.
In cyber security, IoT sensors matter because they are both data sources and attack surfaces. If an attacker spoofs, tampers with, or replaces sensor readings, the system may make decisions based on false information. Weak firmware, exposed management interfaces, and poor device authentication can also let attackers hijack sensors or inject bogus data. Defenses include secure boot, signed updates, strong device identity, encrypted transport, network segmentation, and checking sensor data against other records for anomalies.