Spectrum Stealing via Sybil Attacks in DSA Networks: Implementation and Defense

In this paper, we investigate Sybil attacks on spectrum allocation in distributed dynamic spectrum access (DSA) networks. Using IEEE 802.11 devices as secondary nodes, we demonstrate the feasibility of mounting Sybil attacks in the cognitive radio testbed, in which the malicious node poses as multiple normal secondary nodes with different identities in order to steal more spectrum bands. We also show the impact of the attack through an example and simulation results. A defense strategy using the statistics of beacon intervals is also proposed. Through experimental results, we show the effectiveness of this defense mechanism when there is no interference from external sources as well as in the presence of interference.