Protecting System Information From False Base Station Attacks: A Blockchain-Based Approach

Ensuring secure access to cellular networks is of paramount importance, in which system information (SI) protection plays a crucial role at the initial access stage. While the 3rd generation partnership project (3GPP) released many standardizations to enhance SI protection for preventing users from false base station (FBS) attacks, most of them are centralized solutions which are vulnerable to potential attacks and single-point failures. To address the aforementioned issues, a blockchain-enabled SI protection (BeSI), as a compatible and effective secure access scheme, is developed in this work, which aims at guaranteeing the authenticity and reliability of SI by considering the features of blockchain in immutability, traceability, and decentralization. Then, we derive a mathematical framework to justify the superiority of using blockchain in SI protection. Moreover, by resorting to a Poisson point process as the geographical model for both base stations and FBSs, we thus theoretically analyze the security gain of blockchain and understand the impact of network parameters including redundancy rate, number of confirmation blocks, and the density of base stations. Finally, numerical results are demonstrated to validate the effectiveness of BeSI.

I. Introduction

Security and privacy have been widely recognized as the main issues in cellular networks, which are vulnerable to false base station (FBS) attacks. As shown in Fig. 1, FBS attackers often capture the system information (SI) by lurking around the legitimate base station (called as gNB in 5G), and then replay or broadcast fake SI to user equipments (UEs) with a high transmit power. This actions forces UEs to initiate radio resource control (RRC) setup requests and be associated with the attackers [2], [3]. Once camped with FBS, UE is suffered a series of issues incurred by the attacks, such as eavesdropping, identity theft, and location tracking [4], [5]. In China alone, the total number of FBS activities exceeded 10,000 times in 2019, and 546 times involving 61 illegal and criminal cases in 2020 [6], [7]. From Jan. 2021 to Dec. 2022, over 19,139 monitoring personnel were deployed, collectively conducting surveillance for a total time exceeding 252,180.8 hours to detect FBSs [8], [9]. Recently, the proposed mutual authentications has shown a good potential to address FBS issues in most scenarios [10]. However, it is not a fully covered solution since SI would also be maliciously exploited by FBS without any protection in initial access. Therefore, protecting SI from FBS attacks has become an open issue and drawn much attention from both industry and academia. Fig. 1.

The diagram of FBS attack.