Mobile Ad-Hoc Networks (MANETs) are collections of self-organizing mobile nodes with dynamic topologies and does not have any centralized control in the network. MANET have no clear way of defense mechanism to protect network from security threats, thereby making this network accessible to both legitimate node and authorized node. The absence of centralized administration and openness make MANETs susceptible to many severe attacks such as Wormhole, Blackhole, Rushing, Man in Middle, Sybil attack etc. Wormhole attack is one type of control traffic attack which controls packet transmission by generating false route. If source node selects this false route, malicious node has total control in either forwarding to any destination or dropping it at will. In this paper an attempt has been made to measure the performance of Ad-hoc On Demand Distance Vector Routing (AODV) protocol. Many scenario of wormhole attack is being implemented with varying number of malicious node in the network. A simulation based experiment has been carried out using NS2 simulator for analyzing performance of the network on the basis of three performance matrices-Throughput, average End-to-end Delay and Packet Delivery Function with respect to increasing number of malicious nodes.