Security issues associated with successful operation of cognitive radio networks (CRNs) recently are gaining a lot of attention. In this paper we focus on a specific class of Denial of Service attack that is executed through Channel Eviction Triggering (CET), whereby the adversary nodes unduly invoke mechanisms inherent in CRN operation to protect the licensed users and thus disrupt secondary access to the otherwise idle licensed bands. Skewing the spectrum sensing decision of a CRN through sensing mis-reports is a manifestation of CET attacks. Whereas most studies in the literature focus on making the cooperative sensing more robust against such sensing misreports, we tackle the problem from an incentive perspective and develop strategies to minimize the utility difference of truthful and cheating cognitive radios so as to alleviate the incentive of mis-reporting. Our numerical results verify the effectiveness of the proposed CET defense scheme.