New Privacy Threat on 3G, 4G, and Upcoming 5G AKA Protocols

TLDR

Mobile communications, used by more than two‑thirds of the global population, rely on the 3GPP‑mandated AKA protocol, yet numerous subscriber location attacks have been demonstrated, with some mitigations only in the enhanced 5G AKA. This paper reveals a new privacy attack that breaches subscriber privacy more severely than known location attacks across all AKA variants, including 5G. The attack exploits a previously unknown logical vulnerability that would require dedicated fixes. We demonstrate the attack’s practical feasibility using low‑cost, widely available setups, analyze the vulnerability, and propose countermeasures.

Abstract

Abstract Mobile communications are used by more than two-thirds of the world population who expect security and privacy guarantees. The 3rd Generation Partnership Project (3GPP) responsible for the worldwide standardization of mobile communication has designed and mandated the use of the AKA protocol to protect the subscribers’ mobile services. Even though privacy was a requirement, numerous subscriber location attacks have been demonstrated against AKA, some of which have been fixed or mitigated in the enhanced AKA protocol designed for 5G. In this paper, we reveal a new privacy attack against all variants of the AKA protocol, including 5G AKA, that breaches subscriber privacy more severely than known location privacy attacks do. Our attack exploits a new logical vulnerability we uncovered that would require dedicated fixes. We demonstrate the practical feasibility of our attack using low cost and widely available setups. Finally we conduct a security analysis of the vulnerability and discuss countermeasures to remedy our attack.