Abstract: Research on the security of authentication mechanism has been an important concern in mobile communication, and each generation of mobile communication standards has developed different authentication and key agreement (AKA). With the diversification of access terminal types and access scenarios in 5G IoT, 3GPP has developed an unified user security access authentication mechanism, 5G-AKA, which is still found to be vulnerable after investigation. In this paper, by analyzing the request parameters and response contents in the bidirectional authentication process of 5G-AKA, the risk of user authentication identifier (SUPI) leakage is found, and a SUPI eavesdropping attack model is designed. Based on the UERANSIM and open5gs testing platforms, this paper designs the network topology and experimental scenarios, simulating signaling traffic to validate the aforementioned model.

Key words: security, authentication mechanism, user authentication identifier