A hardware-based watchdog is a monitoring component built into a device or platform that checks whether a system stays within expected behavior and can trigger a reset, halt, or other limit when it does not. Because it operates outside the main application path, it is harder for the monitored software to disable or bypass.
In cyber security, this matters when software may be compromised, misconfigured, or behaving unpredictably. A watchdog can enforce timeouts, stop runaway processes, or cut off unsafe actions even if the application logic fails. Defenders use it to add an independent layer of control for critical services, embedded systems, and autonomous workloads. Attackers try to evade or abuse software-only guardrails, so moving enforcement into hardware can reduce the chance that a malicious payload, buggy agent, or crashed process keeps operating unchecked. It is not a complete defense, but it strengthens containment by making policy harder to ignore.