An approach to mitigate multiple malicious node black hole attacks on VANETs

Inter-vehicular communication is a growing trend among the motor vehicle industry, as part of the shift to the Intelligent Transportation System (ITS) paradigm and the emergence of autonomous vehicles. The benefits of using vehicular communication systems are many: traffic congestion can be abated leading to increased route efficiency and fuel economy; road traffic accidents and fatalities can be prevented; and new services are made available to both driver and passengers. Due to the important functions carried out by these networks, it is essential that communication is secure and free from interference by malicious parties. But the very nature of these networks (i.e. public and dynamically forming, over a shared medium) make them susceptible to certain attack vectors. Black hole attacks are a discernible threat to vehicular communication and the availability of Vehicular Ad Hoc Networks (VANETs). Previously, we proposed a solution to mitigate these attacks in the case of a single malicious node. This countermeasure comprised a detection, accusation, and blacklisting scheme. We now extend that work to also account for cases where multiple malicious nodes are present in the same network. For cases where there is only one malicious node on multiple routes, we add a recursive element to our algorithm to handle additional detections during the accusation phase. Routes containing a node with a pending accusation are also precluded from selection. Where multiple malicious nodes exist on the same route, we adapt our former strategy to allow for multiple concurrent accusations and to find alternate routes to non-malicious nodes that need to be queried when verifying an accusation. We provide validation for our proposal using a simulation model built in NS-3. Results from simulation show the efficacy of our solution in detecting and preventing multiple malicious node black hole attacks in VANETs.