Abstract : The detection of sybil attack is one of the main security challenges in wireless sensor networks (WSNs). The attack is considered as one of the risky threats since an attacker can generate multiple fake identities with false messages to severely impair the normal operation of WSNs. This study proposes a novel sybil attack detection method referred to as CPPR, based on the wireless channel profile and the regulation of transmission power at the sensor nodes. The proposed CPPR mechanism can benefit from the advances in the physical layer at the sensor nodes to regulate their transmission power to prevent many attacks and maintain high detection ratio. The CPPR can also provide low operational overhead and energy consumption. The proposed scheme is shown to provide an average of 95% detection ratio despite the number of sybil nodes in the network.