Information Security: Definitions

Definitions of a few more basic security-related concepts:

VulnerabilityAn existing flaw or weakness in a computer system
Threat (n.)A scenario of potential harm to a system
Attack (n.)(Also: a Breach) An action of harming a system
Exploit (n.)A tool (e.g., software) that misuses a vulnerability to attack a system
Control (n.)(Also: a Security Patch) An action or tool that removes or reduces a vulnerability