Detection of Active Eavesdropping Attack by Spoofing Relay in Multiple Antenna Systems

We consider detection of spoofing relay attack in time-division duplex (TDD) multiple antenna systems where an adversary operating in a full-duplex mode, amplifies and forwards the training signal of the legitimate receiver. In TDD systems, the channel state information can be acquired using reverse training. The spoofing relay attack contaminates the channel estimation phase. Consequently, the beamformer designed using the contaminated channel estimate can lead to a significant information leakage to the attacking adversary. We propose use of the minimum description length source enumeration method based on the data correlation matrix to detect spoofing relay attack exploiting the receiver noise of the spoofing relay. The proposed method is analyzed and its detection performance is illustrated via simulations.