Security and Privacy in O-RAN for 6G: A Comprehensive Review of Threats and Mitigation Approaches

Open Radio Access Network (O-RAN) is a major advancement in the telecommunications field, providing standardized interfaces that promote interoperability between different vendors' technologies, thereby enhancing network flexibility and reducing operational expenses. By leveraging cutting-edge developments in network virtualization and artificial intelligence, O-RAN enhances operational efficiency and stimulates innovation within an open ecosystem. In the context of 6G, the potential capabilities of O-RAN have been significantly expanded, enabling ultra-reliable low-latency communication, terabit-level data rates, and seamless integration of terrestrial and non-terrestrial networks. Despite these benefits, its open architecture paradigm also brings critical security and privacy challenges, which, if not addressed, could compromise network integrity and data confidentiality. This paper conducts a comprehensive investigation into the security vulnerabilities and privacy issues associated with the O-RAN architecture in the context of the evolving 6G landscape, systematically categorizing fundamental vulnerabilities, meticulously examining potential attack vectors, and assessing current and future threats. In addition, this study also examines the existing and emerging security mechanisms of O-RAN and reviews the ongoing standardization activities aimed at strengthening the O-RAN security framework.