Abstract: A blackhole attack is the most emerging security threat in ad-hoc network. Here, malicious node attempt to compromise mobile nodes and drop packet respectively. Blackhole attack may apply through internal or external mode either to disrupt the communication or degrade network performance by dropping the packet. Here, malicious node attempt to get benefitery position into network to compromise the victim node. In Blackhole attack, malicious node attempt to get achievable position into network and start dropping packets respectively. Work observes that all it happened due to weakness of AODV routing protocol. This research work attempts to develop a mitigation algorithm to avoid and prevent genuine nodes from malicious attack. The complete research work is classified into three categories which are without attack, with attack and preventive scenario. Various scenarios based on variable mobile nodes, speed, pause time and area has been configured to observe the impact of blackhole attack and proposed mechanism with different situation. A NS2 simulator has been used to simulate and evaluate the performance of proposed solution. The complete experimental setup concludes that improvement in mobile node increase the network performance but also increase the blackhole impact. Subsequently, improvement in node speed degrades the blackhole impact. The complete work conclude with the fact the performance of modified AODV is similar with traditional AODV routing protocol but give great height in respect to blackhole attack.

Keywords: AODV, MANET, Black-Hole, Ad-hoc.