OT systems, or operational technology systems, are the hardware and software used to monitor and control physical processes such as power grids, factory lines, water treatment plants, pipelines, and building controls. They include devices like PLCs, sensors, human-machine interfaces, and supervisory control platforms. Unlike ordinary IT systems, OT prioritizes safety and uptime, and many components use specialized protocols or run for years with minimal changes.
OT systems matter in cyber security because attacks can move beyond data theft and affect real-world operations. An intruder who changes a controller setting, disables alarms, or disrupts communications can cause downtime, equipment damage, or safety incidents. Defenders often use asset inventory, network segmentation, passive monitoring, and centralized logging to see unusual commands, configuration changes, or device behavior. Good OT security also requires careful telemetry collection so monitoring does not interfere with the process being protected.