CUPS Hijacking in Mobile RAN Slicing: Modeling, Prototyping, and Analysis

In emerging mobile networks, control and user plane separation (CUPS) plays a critical role in scaling the control-plane and user-plane functions independently and enables network virtualization through network slicing. However, a CUPS hijacking attack on a mobile network slicing system and the resulting network performance degradation is yet to be studied. In this work, we investigate the consequences of CUPS hijacking of a radio access network (RAN) slicing system on the overall network performances. We quantify the impacts of CUPS hijacking by designing an Impact Factor metric I, prototype a real-world RAN slicing use case on an end-to-end mobile network test-bed, and systematically analyze the empirical results to reveal the impacts of CUPS hijacking on the network performance. We show a successful CUPS hijacking by a rogue slice owner in a RAN slicing system increases the RAN slice control-plane signalling delay above 2ms, the operational upper-bound of our system, to disrupt the control plane operations by injecting low rate DoS (LDoS) traffic in user-plane. The naive hijacking can degrade throughput performances of the rogue slice as well as a co-located victim slice down to 0 Mbps. We further show that a carefully crafted user-plane traffic by the attacker can regain ~92% of its original user-plane packet delivery success rate while other slices are under the denial of service.