Abstract: As the new generation of mobile communication technology, 5G adopts the service-oriented architecture for the core network, which splits the whole with multiple functions into multiple individuals with independent functions, making the core network more flexible. While the introduction of new architectures and new technologies facilitates communication of users, it also brings some new security issues. This article introduces the security risks of 5G core network element services and corresponding abnormal detection methods, designs a prototype system for detecting abnormalities of 5G core network function services by traffic analyzing and explains the technical routes of each module in the prototype.

Key words: 5G core network, network function service, abnormal detection, traffic analysis, machine learning