A Synchronization Attack and Defense in Energy-Efficient Listen-Sleep Slotted MAC Protocols

As wireless motes are battery powered, many listen-sleep Medium Access Control (MAC) protocols have been proposed to reduce energy consumption. Security issues related to the design of these protocols have, however, largely been ignored. In this paper, we present a novel attack (the synchronization attack) on listen-sleep MAC protocols. This attack can cause 100% message loss and approximately 30% higher energy drain throughout either a cluster or the entire network, with only a single constrained malicious node modifying its schedule. We show this attack can be applied to many slotted listen-sleep protocols such as Sensor MAC (S-MAC), its enhanced version Global Schedule Adoption (GSA), Timeout MAC (T-MAC), Dynamic Sensor-MAC (DSMAC), and Mobile S-MAC (MS-MAC). We propose a heuristically near-optimal threshold-based scheme to defend against large scale synchronization attack. Depending on the traffic rate, our defense can limit the message delay to at most 20% and the message drop to at most 12%. We performed extensive simulations to show the attack and its defense. Our theoretical analysis proves these results in a general listen-sleep framework. An important impact of this work is that without a reliable MAC layer, higher layer secure protocols cannot be developed, e.g. secure routing depends on a reliable exchange of messages and our attack disrupts this exchange.