The Open Radio Access Network (Open RAN) framework, emerging as the cornerstone for Artificial Intelligence (AI)-enabled Sixth-Generation (6G) mobile networks, heralds a transformative shift in radio access network architecture. As the adoption of Open RAN accelerates, ensuring its security becomes critical. The RAN Intelligent Controller (RIC) plays a central role in Open RAN by improving network efficiency and flexibility. Nevertheless, it also brings about potential security risks that need careful scrutiny. Therefore, it is imperative to evaluate the current state of RIC security comprehensively. This assessment is essential to gain a profound understanding of the security considerations associated with RIC. This survey combines a comprehensive analysis of RAN security, tracing its evolution from 2G to 5G, with an in-depth exploration of RIC security, marking the first comprehensive examination of its kind in the literature. Real-world security incidents involving RIC are vividly illustrated, providing practical insights. The study evaluates the security implications of the RIC within the 6G Open RAN context, addressing security vulnerabilities, mitigation strategies, and potential enhancements. It aims to guide stakeholders in the telecom industry toward a secure and dependable telecommunications infrastructure. The article serves as a valuable reference, shedding light on the RIC's crucial role within the broader network infrastructure and emphasizing security's paramount importance. This survey also explores the promising security opportunities that the RIC presents for enhancing network security and resilience in the context of 6G mobile networks. It outlines open issues, lessons learned, and future research directions in the domain of intelligent control in 6G open RAN, facilitating a comprehensive understanding of this dynamic landscape.

翻译：开放无线电接入网（Open RAN）框架作为面向第六代（6G）人工智能（AI）移动网络的基石，正引领着无线接入网络架构的变革性转变。随着Open RAN应用步伐加快，确保其安全性变得至关重要。无线接入网智能控制器（RIC）通过提升网络效率和灵活性在Open RAN中发挥核心作用，然而，它也带来了潜在的安全风险，需要审慎审视。因此，全面评估RIC安全当前态势刻不容缓。本评估对于深刻理解与RIC相关的安全考量至关重要。本综述融合了从2G到5G的RAN安全演进综合分析与RIC安全的深度探索，成为文献中首次对此类议题的全面研究。文中生动展示了涉及RIC的真实世界安全事件，提供了实践见解。研究聚焦于6G Open RAN背景下RIC的安全影响，涵盖安全漏洞、缓解策略及潜在增强措施，旨在引导电信行业相关方构建安全可靠的电信基础设施。本文作为重要参考，揭示了RIC在更广泛网络基础设施中的关键作用，并强调了安全的首要地位。本综述还探讨了RIC在6G移动网络中为增强网络安全性和韧性所提供的安全机遇，概述了6G开放RAN智能控制领域的开放问题、经验教训及未来研究方向，促进了对这一动态格局的全面理解。