Mobile Ad-hoc Networks (MANETs) are a major candidate for delivering next-generation self-organizing technologies, and are applicable in multiple environments (i.e. IoT, VANETs, disaster-zones, etc.). The main focus of research, however, is geared towards routing efficiency, self-organization and other "management" issues; hence, the resulting native protocols tend to be vulnerable to various attacks. Over the years, work has been done to improve protocol security, with different solutions proposed for different types of attacks. These solutions, however, often compromise routing efficiency or require network overhead, and many are themselves a new attack venue.

In this talk one major topologically based attack against the Optimized Link State Routing protocol (OLSR) and the similar OSPF-m will be described. We will show how the attack can manifest into a full DoS or the gray- or black-hole attacks. We then describe a solution using fictitious nodes for defending OLSR from these attacks, employing the same tactics used by the attack itself for defense.