Dynamic Defense Strategy Against DoS Attacks Over Vehicular Ad Hoc Networks Based on Port Hopping

To fight against denial of services (DoS) attacks on vehicular ad hoc networks, which can cause congestion over networks and degrading the user's experience, a lot of detective techniques and schemes have been proposed. However, the complex ones cannot keep pace with the growth of vehicle networks. In this paper, we propose a simple but effective defense strategy scheme inspired by the port-hopping mechanism, which advantage is manifested in that the detection and filtering off of malicious packets launched by attackers can be achieved without any change in existing protocol. First, we design a dynamic defense strategy scheme to puzzle a DoS attacker, where the specific defense strategy will change according to a scheme of time. To mitigate the losses caused by an attacker whose goal is to probe the vulnerable services' ports contained in the UDP/TCP headers between vehicle-to-vehicle or vehicle-to-infrastructure, we add some security services' ports that are valueless to attackers. Second, we give the specific construction of such a defense strategy scheme reflected as a matrix and a security analysis with respect to detecting the probed ports. At last, in comparison with the non-strategy defense scheme, simulations considering some parameters are conducted, which can show that our scheme is an effective defense scheme used for protecting VANETs.