The inability of a system or component to perform required functions within acceptable performance parameters. Failures result from hardware malfunctions, software bugs, misconfigurations, or resource exhaustion, potentially causing service disruptions.

A security alert incorrectly flagging legitimate activity as malicious or suspicious. Excessive false positives create alert fatigue, wasting analyst time and potentially masking real threats among noise.

A network security device that filters traffic between networks based on predefined rules, blocking unauthorized access while permitting legitimate communications. Firewalls form the first line of defense in network perimeter security.