Reduce to the MACs -- Privacy Friendly Generic Probe Requests

TL;DR

This paper proposes a method to enhance user privacy in Wi-Fi networks by minimizing probe request information elements, making devices indistinguishable and significantly increasing anonymity.

Contribution

It introduces generic probe requests that remove unnecessary information, demonstrating that minimal IEs can greatly improve device anonymity without hindering connection setup.

Findings

82.55% of devices share the same anonymity set with minimal IEs

Large IE sets do not necessarily speed up connection establishment

Removing all but Supported Rates greatly enhances privacy

Abstract

Abstract. Since the introduction of active discovery in Wi-Fi networks, users can be tracked via their probe requests. Although manufacturers typically try to conceal Media Access Control (MAC) addresses using MAC address randomisation, probe requests still contain Information Elements (IEs) that facilitate device identification. This paper introduces generic probe requests: By removing all unnecessary information from IEs, the requests become indistinguishable from one another, letting single devices disappear in the largest possible anonymity set. Conducting a comprehensive evaluation, we demonstrate that a large IE set contained within undirected probe requests does not necessarily imply fast connection establishment. Furthermore, we show that minimising IEs to nothing but Supported Rates would enable 82.55% of the devices to share the same anonymity set. Our contributions provide a significant advancement in the pursuit of robust privacy solutions for wireless networks, paving the way for more user anonymity and less surveillance in wireless communication ecosystems.