The Internet of Things (IoT) is an important technological turning point, transforming industries such as smart homes, industrial applications, healthcare, and agriculture. As IoT continues to expand alongside the rollout of 5G networks, it becomes increasingly vital to manage the inherent security vulnerabilities offered by connected devices. This chapter delves further into IoT systems, starting with their concept, evolution, and key components. It delves further into essential applications and the expanding security difficulties they confront, namely in the areas of vulnerability analysis, intrusion detection, and malware. Furthermore, the chapter discusses the most recent security improvements, such as secure communication protocols and SDN-based policy administration. This chapter stresses the importance of effective IoT security techniques, providing practical insights into fraud detection and other critical security applications.