A mobile ad hoc network is an infrastructure less network where mobile nodes position themselves in an abrupt fashion or most of the time communication takes place while nodes are moving. Such networks are also featured by dynamic topology i.e. the topology changes from time to time. Because of autonomous nature and dynamic behavior of MANET (Mobile Ad hoc NETwork) any node from external environment can add itself to the network and behave maliciously leading to various commonly known attacks e.g. flooding attacks, link withholding attack, link spoofing attack, replay attack, wormhole attack, colluding mis-relay attack, etc.