Mobile ad hoc networks (MANETs) consist of a collection of wireless mobile nodes which dynamically exchange data among themselves without the need of fixed infrastructure or a wired backbone network. In MANET nodes are typically distinguished by their limited power, processing, and memory resources as well as high degree of mobility. In such networks, the wireless mobile nodes may dynamically enter the network as well as leave the network at any time. Due to limited transmission range of wireless network nodes, multiple hops are usually needed for a node to exchange information with any other node in the network. Thus routing is a crucial issue in the design of MANET. In this paper we deal with misbehaving nodes in mobile ad hoc networks (MANETs) that drop packets supposed to be relayed, whose purpose may be either saving their resources or launching a DoS attack. This paper also nvestigates the serious and harmful attack, "Denial of Service" (DOS) that exhibit in multiple forms across different layers of protocol stack. To defend against this attack, a novel Cross Layer Based Intrusion Detection System that performs accurate diagnosis of malicious attacks by analyzing the pattern of trace files, overcome the demerits such as false positives present in traditional IDS, thereby providing secure communication between nodes that communicate with each other to route the traffic from source to destination and also increase the efficiency of the network performance. The simulations conducted in ns-2 proved that this work has achieved high performance with fever overheads.