Wireless sensor networks (WSNs) play a major role in the 6G and beyond systems, thus it has been one of the major research fields in the past few decades. The deployment of WSNs in future communication networks has been investigated in literature and has shown great potential for many applications such as healthcare, industrial control and monitoring, agriculture, etc. However, there are many challenges that arise from deploying such networks to ensure efficient and reliable operation, such as energy efficiency, security, reliability, scalability, and adaptability. This article explores one of the security threats in WSNs, which is the sinkhole attack, and investigates the research projects in this area. This study highlights the limitations of the state-of-the-art research in this field, then designs and simulates a secured routing protocol to detect and mitigate Sinkhole attacks in mobile wireless sensor networks (MWSNs) and ensure their security and availability. The proposed Directional Routing Reflector Protocol is proven to achieve steady and reliable performance in threat detection, while maintaining the energy efficiency and the lifetime of the sensor nodes.