Objectives: IoT is the blooming technology in the recent years. It connects anything at any time at anywhere through Internet. It makes the human life to be sophisticated. It provides the comfort zone for the human by unitizing the automation process through Internet facility. Inasmuch as things are connected through Internet, providing security is necessary. From many security requirements, network security is the major security requirement in IoT. Many researchers are emphasizing security challenges in RPL-based networks, which are a major concern in IoT. One of the most critical challenges within these networks is the rank attack. Methods: This paper proposes a secured STARO framework to handle rank attack issues in IoT. The STARO framework accommodates three techniques, i.e., Level-based Rank Attack Detection Technique (LEACE), Received Signal Strength Indicator (RSSI)-based Rank Attack Detection Technique (RACE), and Location-based Rank Attack Detection Technique (LACE). Findings: The model is validated through Cooja simulator over Contiki operating system. It performs better as far as packet delivery ratio, throughput and attack detection rate is concerned. Novelty: It is extremely challenging to identify rank attacks in RPL networks. Although there are a few approaches to discover rank attacks in RPL-based IoT networks, no comprehensive framework is yet formulated to identify rank attacks based on objective functions. This paper proposes a framework that integrates three approaches to fill this gap. The proposed framework identifies rank attacks using the objective function (OF) used in RPL network construction.