Defending packet dropping attacks based on dynamic trust model in wireless ad hoc networks

Rapid advances in wireless ad hoc networks lead to increase their applications in real life. Since wireless ad hoc networks have no centralized infrastructure and management, they are vulnerable to several security threats. Malicious packet dropping is a serious attack against these networks. In this attack, an adversary node tries to drop all or partial received packets instead of forwarding them to the next hop through the path. A dangerous type of this attack is called black hole. In this attack, after absorbing network traffic by the malicious node, it drops all received packets to form a denial of service (DOS) attack. In this paper, a dynamic trust model to defend network against this attack is proposed. In this approach, a node trusts all immediate neighbors initially. Getting feedback from neighbors´ behaviors, a node updates the corresponding trust value. The simulation results by NS-2 show that the attack is detected successfully with low false positive probability.