Cognitive radio is an empowering innovation that guarantees to achieve spectrum utilization. To manage the muddled wireless condition, cooperative spectrum sensing (CSS) has been proposed to make use of the assorted variety in cognitive radio networks (CRNs). However, due to the simplicity of CRNs, CSS are vulnerable to security threats. Spectrum sensing data falsifcation (SSDF) attacker is one of the attackers in CSS. In the SSDF attack, malicious secondary users (MSUs) send false sensing decisions to the fusion center, which signifcantly degrades detection accuracy. In this paper, to identify MSUs, a modifed delivery based scheme is proposed, where a minimum number of samples are considering for sensing. The proposed security scheme is shown to successfully alleviate the impact of MSUs on global decision making, which enhances the achievable throughput of an honest secondary user.