Removal of Malicious Nodes Launching Blackhole Attack in MANETs

Mobile Adhoc Network (MANET) have been widely used for various applications such as military crisis operations and emergency rescue operations. The infrastructure-less nature and the dynamic topology features of MANET makes these networks highly vulnerable to various security issues .The primary requirement for the establishment of communication among nodes in mobile ad hoc networks is that nodes should cooperate with each other. With the existence of malevolent nodes, this requirement may lead to serious security concerns; for example, such malicious nodes may disrupt the routing process. In this context, preventing or detecting malicious nodes launching collaborative blackhole attacks is a challenge. This paper resolves this issue by designing a routing mechanism based on dynamic source routing (DSR), referred to as the cooperative bait detection scheme (CBDS). In this scheme, it integrates the proactive and reactive defense architecture and randomly cooperates with a stochastic adjacent node. By using the address of an adjacent node as a bait destination address to bait malicious nodes to send a reply message (RREP) and strange nodes are detected using a reverse tracing technique thereby ensures security. Simulation results are provided, showing that in the presence of malicious node attacks, the CBDS outperforms the DSR protocol in terms of performance metrics such as throughput and packet delivery ratio.