An OpenRAN Security Framework for Scalable Authentication, Authorization, and Discovery of xApps With Isolated Critical Services

The OpenRAN initiative promotes an open Radio Access Network (RAN) and offers operators fine-grained control over the radio stack. To that end, O-RAN introduces new components to the 5G ecosystem, such as the near real-time RAN Intelligent Controller (near-RT RIC) and the accompanying extensible Applications (xApps). The introduction of these entities expands the 5G threat surface. Furthermore, with the movement from proprietary hardware to virtual environments enabled by Network Functions Virtualization (NFV), attack vectors that exploit the existing NFV attack surface pose additional threats. To deal with these threats, we propose the xApp repository function (XRF) framework for scalable authentication, authorization, and discovery of xApps. To harden the XRF microservices, we isolate them using Intel Software Guard Extensions (SGX). We benchmark the XRF modules individually and compare how different microservices behave in terms of computational overhead when deployed in virtual and hardware-based isolation sandboxes. Our evaluation shows that the XRF framework scales efficiently in a multi-threaded Kubernetes environment. The isolation of the XRF microservices introduces different amounts of processing overhead depending on the sandboxing strategy. Finally, a security analysis is conducted to show how the XRF framework addresses chosen key issues from the O-RAN and 5G standardization efforts.