Cascading Attacks on Wi-Fi Networks: Theory and Experiments

摘要

We unveil the existence of a vulnerability in Wi-Fi (802.11) networks, which allows an adversary to remotely launch a denial-of-service (DoS) attack that propagates both in time and space. This vulnerability stems from a coupling effect induced by hidden nodes. Cascading DoS attacks can congest an entire network and do not require the adversary to violate any protocol. We demonstrate the feasibility of such attacks through experiments with real Wi-Fi cards, theoretical analysis, and ns-3 simulations. The experiment shows that an attacker can cause the throughput of a node outside its communication range to vanish. To gain insight into the root causes of the attack, we model the network as a dynamical system and analyze its limiting behavior and stability. The model predicts that a phase transition (and hence a cascading attack) is possible in linear networks when the retry limit parameter of Wi-Fi is greater or equal to 7, and also characterizes the phase transition region in terms of the system parameters.