This paper aims at designing, building, and simulating a secured routing protocol to defend against packet dropping attacks in mobile WSNs (MWSNs). This research addresses the gap in the literature by proposing Configurable Secured Adaptive Routing Protocol (CSARP). CSARP has four levels of protection to allow suitability for different types of network applications. The protocol allows the network admin to configure the required protection level and the ratio of cluster heads to all nodes. The protocol has an adaptive feature, which allows for better protection and preventing the spread of the threats in the network. The conducted CSARP simulations with different conditions showed the ability of CSARP to identify all malicious nodes and remove them from the network. CSARP provided more than 99.97% packets delivery rate with 0% data packet loss in the existence of 3 malicious nodes in comparison with 3.17% data packet loss without using CSARP. When compared with LEACH, CSARP showed an improvement in extending the lifetime of the network by up to 39.5%. The proposed protocol has proven to be better than the available security solutions in terms of configurability, adaptability, optimization for MWSNs, energy consumption optimization, and the suitability for different MWSNs applications and conditions.