1. A transmission channel that may be used to transfer data in a manner that violates security policy. 2. An unintended and/or unauthorized communications path that can be used to transfer information in a manner that violates an information system (IS) security policy. 3. A channel which allows information to flow in violation of the System Security policy. Note: Covert channels can occur via mechanisms other than explicitly designed channels. For example, a covert timing channel may transmit information by inducing variations in system response time. 4. The use of a mechanism not intended for communication to transfer information in a way which violates security. 5. A communications channel that allows a process to transfer information in a manner that violates the system's security policy. A covert channel typically communicates by exploiting a mechanism not intended to be used for communication. 6. A communications channel that allows a process to transfer information in a manner that violates the system's security policy. See also: Covert Storage Channel, Covert Timing Channel.