Vulnerabilities of Geocast Message Distribution

Geocast refers to the distribution of messages within a geographic destination region. This makes it an important paradigm for the application to vehicular ad hoc networks (VANETs), because most safety-related information needs to be delivered to all vehicles in a certain area. As a central requirement for such safety applications, the protocol must be very robust against faults, regardless if caused accidentally or intentionally. In this paper, we examine the case of intentionally disturbances caused by attackers, i.e. the security of Geocast. We analyze weaknesses, describe potential attacks and discuss their respective effects. In a detailed study, we focus on a particularly sneaky attack, selective jamming, and show its impact on Geocast using simulations in highway and city scenarios. Particularly in highway scenarios, it is possible to disrupt Geocast flows completely using this attack.