With the evolution and popularization of mobile communication systems, especially for access to data services, it becomes increasingly important to have a closer look at security systems. From analog systems to the fourth generation, many changes and evolutions occurred. This makes possible to question whether mobile networks have sufficiently secure systems, and what vulnerabilities we should be aware of. Due to the widespread risk of attacks on mobile communications, telecommunication companies are increasingly emphasizing telecommunication security technologies specifically in fourth generation (4G) technology, in order to ensure the main security functions to provide an efficient service to its customers.