Plausibility is the degree to which a claimed scenario is technically and operationally believable. In cyber security, it helps analysts separate a realistic threat from a dramatic but unsupported claim. A plausible scenario fits known system behavior, attacker capabilities, access requirements, and common failure modes. An implausible one may be possible in theory, but it lacks a credible path to execution.
This concept matters in incident response, threat modeling, and AI safety reviews because defenders must prioritize limited time and budget. Attackers often rely on plausible stories to trick users, such as convincing phishing lures or believable fake alerts. Defenders use plausibility checks to judge whether a report, exploit chain, or risk claim deserves urgent action, more testing, or stronger controls. Good security work does not ignore unlikely events; it ranks them by evidence and operational feasibility.