Design of Transport Layer Based HybridCovert Channel Detection Engine

Computer network is unpredictable due to information warfare and is prone to variousattacks. Such attacks on network compromise the most important attribute, the privacy. Most of suchattacks are devised using special communication channel called ``Covert Channelʹʹ. The word ``Covertʹʹstands for hidden or non-transparent. Network Covert Channel is a concealed communication path withinlegitimate network communication that clearly violates security policies laid down. The non-transparencyin covert channel is also referred to as trapdoor. A trapdoor is unintended design within legitimatecommunication whose motto is to leak information. Subliminal channel, a variant of covert channel workssimilarly except that the trapdoor is set in a cryptographic algorithm. A composition of covert channel withsubliminal channel is the ``Hybrid Covert Channelʹʹ. Hybrid covert channel is homogenous orheterogeneous mixture of two or more variants of covert channels either active at same instance or atdifferent instances of time. Detecting such malicious channel activity plays a vital role in removing threatto the legitimate network. In this paper, we present a study of multi-trapdoor covert channels andintroduce design of a new detection engine for hybrid covert channel in transport layer visualized in TCPand SSL