RPL is a de facto routing protocol for IoT (Internet of Things). In this paper, an efficient IDS (intrusion detection system) is proposed to solve a major security vulnerability of RPL, which is called fabricated parent change. We show that many well-known attacks and security breaches are carried out via this vulnerability. The proposed method, which is called PCC-RPL (Parental Change Control RPL), prevents unsolicited parent changes by utilizing the trust concept. In PCC-RPL, all parents monitor their children behavior continuously. When a malicious activity is detected by the parent, it decreases the child's trust level and informs the root by sending a suspicion message. Our simulation results indicate that PCC-RPL can detect almost all common RPL attacks with an acceptable accuracy compared to a well-known method. Low control overhead, low energy consumption, short attack detection delay, and high precision are the main features of the proposed scheme.
