Wireless networks are computer networks that are not connected by cables of any kind. The use of wireless network enables enterprises to avoid the costly process of introducing cables into buildings or as a connection between different equipment locations. Wireless networks are susceptible to many attacks. One such specific attack is a blackhole attack in which malicious node falsely claiming itself as having the fresh and shortest path to the destination. In this paper, we propose a method for avoiding blackhole attack without the constraint of special hardware and dependency on physical medium of wireless network. The proposed methods forms link disjoint multi-path during path discovery to provide greater path selection in order to avoid malicious nodes in the path using legitimacy table maintained by each node in the network. By making use of bell curve, Non-malicious nodes gradually isolate the blackhole nodes and avoid them while making path between source and destination.Various related works were also studied for knowing the related works which have been carried out in order to avoid blackhole attack in a network. They had some flaws too,which were overcome by the proposed system.Proposed system helps us in defending against the blackhole attack without any requirement of hardware and special detection node.