  We unveil the existence of a vulnerability in Wi-Fi, 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, extensive ns-3
simulations, and theoretical analysis. The simulations show that the attack is
effective both in networks operating under fixed and varying bit rates, as well
as ad hoc and infrastructure modes. To gain insight into the root-causes of the
attack, we model the network as a dynamical system and analyze its limiting
behavior. The model predicts that a phase transition (and hence a cascading
attack) is possible when the retry limit parameter of Wi-Fi is greater or equal
to 7, and explicitly characterizes the phase transition region in terms of the
system parameters.
