Abstract

The Open Radio Access Networks movement (O-RAN) drives the industry toward open interfaces such as the open fronthaul (O-FH) and enables RAN virtualization and intelligence through AI by augmenting the RAN with radio intelligent controllers capable of hosting various applications that optimize the RAN’s performance and potentially bolster its security.
However, this openness and intelligence in design expand the attack surface and present new challenges in ensuring network security. In this thesis we present two contributions aimed at addressing security challenges both inherited from previous RANs or specific to the O-RAN.
We address the Base Transceiver Station Resource Depletion (BTS-RD) attack, an attack that exploits the lack of integrity check in the Radio Resource Control protocol to deplete the BTS resources. However, in this work, we leverage O-RAN intelligence to introduce a novel O-RAN-compliant detection solution that detects variations of the BTS-RD attack. Our solution, the “BTS-Band”, employs a Bidirectional Long Short-Term Memory Autoencoder (BiLSTM-AE) for detecting anomalies. Moreover, to promote trust we integrate Shapley additive explanations to provide explanations of the model’s decisions. To evaluate the performance of the BTS-Band we built a 5G testbed based on OpenAirInterface, on top of which, we emulate and extract benign and attack traffic to train and test our solution. Accordingly, the BTS-Band achieves an average F1-score of 92.4% in detecting multiple BTS-RD variations.
Second, we shift the focus to our work on assessing the security of the O-FH. Particularly, the security of the newly introduced Synchronization Plane (S-plane) is interesting for its sensitivity to latencies and performance expectations that makes integrating appropriate security measures challenging. We identify emerging security threats on the S-plane, discuss their impact on O-RAN synchronization topologies, and accordingly present countermeasures.
As such, our work contributes to enhancing the resilience and security of next-generation open RAN systems.