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 grayhole attack in which malicious node falsely claiming itself as having the fresh and shortest path to the destination. In the initial stage it uses a proactive architecture, i.e. uses a Bait id concept for the detection of malicious nodes present in the network. Upon the completion of initial stage it switches to reactive defense strategy. The secure routing protocol resulted in increased packet delivery ratio and reduced overhead ratio. The extended defense routing protocol worked efficiently for the malicious node detection and removal in case of Co-operative Black Hole attack resulting in increased network performance. This paper proposes a detection scheme called the cooperative bait detection scheme (CBDS), which aims at detecting and preventing malicious nodes launching grayhole/collaborative blackhole attacks in MANETs. This paper attempts to resolve this issue by designing a dynamic source routing (DSR)-based routing mechanism, which is referred to as the cooperative bait detection scheme (CBDS), that integrates the advantages of both proactive and reactive defense architectures. Our CBDS method implements a reverse tracing technique to help in achieving the stated goal. Proposed system helps us in defending against the blackhole attack without any requirement of hardware and special detection node.