Analysis And Research On Security Flaws Of LTE Roaming Networks

With the increase of international communication,the demand and application of the roaming service are also on the increase.The multi-node deployment and operator interoperability in LTE roaming networks have introduced new problems to LTE system security.At present,experts and scholars at home and abroad mainly focus on non-roaming networks,and they pay less attention to the security of LTE roaming networks.In order to ensure the legal rights of roaming users,it is necessary to conduct research on the security of LTE roaming networks.First,this paper excavates and analyzes the following three kinds of security vulnerabilities in terms of system integrity and usability:1.Integrity vulnerability of the detachment process.The detachment process and related networks element behaviors involved are analyzed in detail,and then the user false online vulnerability due to lack of storage of the"UE purged in MME" flag in the HSS are discovered;2.Availability vulnerability of DNS service.The parallel relationship of the ESM and EMM sub-layers in the MME entity is analyzed in detail,and then the vulnerability of DNS availability caused by the parallel execution of the authentication process are discovered;3.Forgement vulnerability of Diameter packets.The application of Diameter protocol on S6a and S9 interfaces is analyzed in detail,and then under the condition when the border proxy is controlled,the exploits of AVP and its corresponding consequences are studied.Secondly,in order to verify the above security vulnerabilities,this paper builds an LTE networks simulation platform based on OAI,then experiments are carried out and the verification and analysis of the three proposed security flaws are given.Finally,according to the results of theoretical analysis and experiments,this paper presents two enhancements including abnormal traffic detection based on CUSUM algorithm and service availability enhancement based on multi-level cache.Then the effectiveness of the proposed enhancements are analyzed and verified.