Authenticating the Sector Sweep to Protect Against Beam-Stealing Attacks in IEEE 802.11ad Networks

Millimeter-wave communication systems use steerable antennas with directional beams to overcome high attenuation. Transceivers mutually train their beams to provide strong gains in the desired direction. Unfortunately, state-of-the-art beam-training protocols, such as the IEEE 802.11ad sector sweep, do not protect against malicious behavior. As revealed recently, attackers can inject forged feedback into the sector sweep to cause devices to steer their beams to other than the indented directions. To protect against this kind of beam-stealing, we propose a sector sweep with authentication (SSA) that extends the prevalent sector sweep with an authentication scheme. Doing so, we ensure that devices only accept the feedback from their intended peers. A combination of simulations in ns-3 and measurements on off-the-shelf devices reveals that the performance overhead of SSA is only 7.3% in comparison to the original sector sweep.