Abstract
As mobile wireless ad hoc networks have different characteristics from wired networks and even from standard wireless networks, there are new challenges related to security issues that need to be addressed. Many intrusion detection systems have been proposed and most of them are tightly related to routing protocols, such as Watchdog/Pathrater and Routeguard. These solutions include two parts: intrusion detection (Watchdog) and response (Pathrater and Routeguard). Watchdog resides in each node and is based on overhearing. Through overhearing, each node can detect the malicious action of its neighbors and report other nodes. However, if the node that is overhearing and reporting itself is malicious, then it can cause serious impact on network performance. In this paper, we overcome the weakness of Watchdog and introduce our intrusion detection system called ExWatchdog. The main feature of the proposed system is its ability to discover malicious nodes which can partition the network by falsely reporting other nodes as misbehaving and then proceeds to protect the network. Simulation results show that our system decrease the overhead greatly, though it doe not increase the throughput obviously.