On the Security of Carrier Phase-based Ranging

TL;DR

This paper evaluates the security of multicarrier phase-based ranging systems, revealing their vulnerability to distance decreasing relay attacks, and demonstrates feasible attacks through simulations and experiments, questioning their suitability for critical applications.

Contribution

It is the first comprehensive analysis of the security vulnerabilities of phase-based ranging, especially focusing on distance reduction attacks and their practical feasibility.

Findings

Successfully reduced estimated range from over 50 m to less than 3 m

Demonstrated vulnerability of phase-based ranging to relay attacks

Discussed limitations of countermeasures against such attacks

Abstract

Multicarrier phase-based ranging is fast emerging as a cost-optimized solution for a wide variety of proximity-based applications due to its low power requirement, low hardware complexity and compatibility with existing standards such as ZigBee and 6LoWPAN. Given potentially critical nature of the applications in which phase-based ranging can be deployed (e.g., access control, asset tracking), it is important to evaluate its security guarantees. Therefore, in this work, we investigate the security of multicarrier phase-based ranging systems and specifically focus on distance decreasing relay attacks that have proven detrimental to the security of proximity-based access control systems (e.g., vehicular passive keyless entry and start systems). We show that phase-based ranging, as well as its implementations, are vulnerable to a variety of distance reduction attacks. We describe different attack realizations and verify their feasibility by simulations and experiments on a commercial ranging system. Specifically, we successfully reduced the estimated range to less than 3 m even though the devices were more than 50 m apart. We discuss possible countermeasures against such attacks and illustrate their limitations, therefore demonstrating that phase-based ranging cannot be fully secured against distance decreasing attacks.