An Air Interface Signaling Protection Function for Mobile Networks: GSM Experiments and Beyond

The growing number and variety of expected use cases for mobile networks puts an increasing emphasis on security, including ensuring the availability and integrity of the network and its services. In this study, we consider the possibility of adding a layer of protection against intentionally malicious control plane signaling over the air interface. A proof-of-concept protection function for the control plane of the GSM CS domain has been developed and laboratory tests for two types of availability attacks are presented, the first is intentionally malformed or out-of-sequence messages, and the second is flooding for resource exhaustion. The concept should be applicable also to future 5G systems, and we discuss some considerations for extending it to LTE, as a step in that direction.