Mitigating Energy Depletion Attacks in IoT via Random Time-Slotted Channel Access

Energy depletion attacks represent a challenging threat towards the secure and reliable deployment of low-power Internet of Things (IoT) networks. Indeed, by simply transmitting canning standard-compliant packets to a target IoT device, an adversary can quickly exhaust target devices available energy and reduce network lifetime, leading to extensive Denial-of-Service (DoS). Current solutions to tackle energy depletion attacks mainly rely on ex-post detection of the attack and the adoption of follow-up countermeasures. Still, the cited approaches cannot prevent external adversaries from sending wireless packets to target devices and draining down their energy budget. In this paper, we present RTSCA, a novel countermeasure to energy depletion attacks in IoT networks, that leverages Random Time-Slotted Channel Access. RTSCA randomizes channel access operations executed by a couple of directly-connected IoT devices operating through the IEEE 802.15.4 MAC, significantly reducing the time window of opportunity for the attacker, with little-to-none energy cost on legitimate IoT devices. RTSCA also includes a detection mechanism targeted to the recently-introduced Truncate-after-Preamble (TaP) energy depletion attacks, that leverages the observation of error patterns in the received packets. We carried out an extensive performance assessment campaign on real Openmote-b IoT nodes, showing that RTSCA forces the adversary to behave as a (sub-optimal) reactive jammer to achieve energy depletion attacks. In such a setting, the adversary has to spend between 42:5% and 55% more energy to carry out the attack, while at the same time having no deterministic chances of success.