Radio Access Network Attacks: A Comprehensive Survey

5G is the most recent technology standard for cellular networks, which phone companies began deploying worldwide in 2019. One of its key elements is the Radio Access Networks (RAN), which further facilitates the enabling of the basic 5G capabilities: enhanced Mobile Broadband (eMBB), Massive Machine-Type Communication (mMTC), and Ultra-Reliable Low-Latency Communication (URLLC). To meet the hyperscalability, high performance, and low latency required by future 5G use cases, 5G is distributed, virtualized, shared, and architecturally more complex than previous generations. However, this technological advance raises concerns, especially related to cyber security. Virtualization, the use of cloud-based resources and the distribution from edge computing significantly expand the attack surface. New attack vectors due to increased bandwidth, software-defined network, slicing, and the deployment of Internet of Things devices, made RANs prone to new cyber menaces. Furthermore, these issues can cause severe economic and social losses since 5G networks are envisioned to be the backbone for critical infrastructure across various sectors like smart cities, smart health, transportation, and smart grids. So, this survey systematically categorizes security menaces in Radio Access Networks. This paper describes 29 attacks common to RAN scenarios, studies the findings on the implications of cyberattacks in RANs, establishes the definition of five classes of RAN attacks, details each identified attack, justifies categorizing each attack in the appropriate class, and presents the countermeasures most studied for each class of RAN attacks.