Cyber-physical systems are environments where software, networked devices, sensors, and controllers directly influence physical equipment and processes. Examples include factory lines, power grids, building controls, medical devices, and other operational technology that must keep working in the real world, not just on a screen.
In cyber security, these systems matter because a vulnerability can affect safety, uptime, and equipment integrity, not only data confidentiality. An attacker who reaches a controller, sensor, or remote management interface may be able to change setpoints, stop a process, falsify readings, or trigger unsafe behavior. Defenders use asset inventory, segmentation, secure remote access, monitoring, and careful vulnerability validation to reduce that risk. In practice, cyber-physical security is about understanding what each device controls, how failure would affect operations, and how to test or patch without disrupting the physical process.