An intermittent fault is a defect that appears only under certain conditions, such as temperature changes, vibration, power fluctuations, or specific timing, and then disappears before it can be easily observed. Because the problem is inconsistent, it is often hard to reproduce in a lab or during troubleshooting. In practice, this makes the fault look random even when it has a real physical or logical cause.
In cyber security, intermittent faults matter because they can imitate the effects of malware, unstable drivers, failed storage, or network attacks. A defender may see dropped connections, corrupted data, or system crashes that come and go, which slows diagnosis and can hide the true root cause. Attackers can also exploit unreliable systems by triggering failures at the right moment, while defenders look for patterns with logs, repeated testing, hardware checks, and controlled stress tests. The key lesson is to verify unstable systems carefully before trusting them.