Mobile ad hoc networks are comprised of nodes that must cooperate to dynamically establish routes using wireless links. Routes may involve multiple hops with each node acting as a host and router. Since ad hoc networks typically work in an open un-trusted environment with little physical security, they are subject to a number of unique security attacks like wormhole attack. The wormhole attack is considered to be a serious security attack in multi-hop ad hoc networks. In wormhole attack, attacker makes tunnel from one end of the network to the other, nodes stay in different location on two ends of tunnel believe that they are true neighbours and makes conversation through the wormhole link. Unlike many other attacks on ad-hoc routing, a wormhole attack cannot be prevented with cryptographic solutions because intruders neither generate new, nor modify existing, packets, but rather forward existing ones. In this paper a simple technique to effectively detect wormhole attacks without the need for special hardware and/or strict location or synchronization requirements is proposed. The proposed technique makes use of variance in routing information between neighbours to detect wormholes. The base of dissertation is to find alternative path from source to second hop and calculate the number of hops to detect the wormhole.

Adhoc network wormhole threshold AODV