Vulnerability Analysis Of 5G Core Network And Implementation Of The Verification System

With the development of mobile communication technology,5G plays an important role in the Internet of Things,Telematics,and military defense,and the security of the core network,which is an important part of the 5G system,is also very important.Vulnerabilities may be inherited and introduced to the 5G core network due to the selective retention and improvement of legacy protocols,as well as the adoption of Internet protocols and the Service-based Architecture(SBA)for networks.Vulnerability is weakness,and vulnerability analysis of 5G core networks focuses on uncovering potential security weaknesses in protocols and network architectures,and enabling the design of attack scenarios and verification of the validity of the results.Some of the current problems in protocol and network architecture security research are as follows:(1)although vulnerability studies of existing protocols point out that there is a risk of user privacy leakage,they do not identify specific privacy field values;(2)most of the security studies for SBA architecture have conducted theoretical analysis of the overall architecture.Therefore,this thesis designs two attack models for the above problems and builds a vulnerability verification system,which finds several vulnerabilities.The main work of this thesis is as follows:1.A vulnerability of Subscriber Permanent Identifier(SUPI)leakage in the 5G-AKA protocol is proposed.Firstly,this thesis analyzes different business processes and message flows to point out the user privacy fields that are at risk of leakage.Secondly,the vulnerability analysis of the process of the 5G-AKA two-way authentication mechanism and the service interface provided by the authentication entity is conducted,and then the existence of authentication parameters that can be maliciously exploited during the request response process is identified.Finally,a SUPI eavesdropping attack scheme is designed,pointing out the user privacy SUPI fields that lead to leakage and also interfere with user services.2.A vulnerability to malicious cancellation of network Function(NF)in the SB A architecture is proposed.Firstly,the thesis provides a detailed analysis of the service and API information of the authentication network function based on the characteristics of the SBA architecture of the core network and the flow of network element interaction.Finally,it is found that at the control level attackers can disguise as legitimate network elements and maliciously use APIs lacking authorization to launch attacks,and a malicious logout attack scheme for NF is designed.3.A vulnerability verification system for 5G core is designed and implemented.This thesis designs this system to address the problem of lack of systematic verification for vulnerability studies.System includes three major modules:5G core functional module,packet construction and transmission,and traffic collection.The results of the model are validated in the system by designing attack scripts and implementing attack behaviors.The results of the SUPI eavesdropping attack model validation are that both single-user and multi-user registration scenarios have the risk of SUPI leakage,and the results of the NF malicious logout attack model validation are that four attack effects are derived from the attacks on different NFs.