A watchdog timer is a safety mechanism in embedded devices and other systems that forces a reboot when software stops responding. A healthy program must periodically “feed” the timer; if it hangs, crashes, or fails to report in time, the device restarts to recover from a fault.
In cyber security, watchdog timers matter because attackers can abuse them for persistence or disruption. Malware may keep the watchdog satisfied so a stuck or hidden process stays alive, or it may interfere with shutdown and reboot paths so cleanup actions trigger repeated restarts. Defenders watch for unexpected reboot loops, protect boot and recovery binaries, and check whether malware is using the device’s own safety features against it. On IoT gear, that can turn a simple crash recovery tool into an obstacle to removal.