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Security and Communication Networks
Volume 2017, Article ID 6235484, 21 pages
https://doi.org/10.1155/2017/6235484
Research Article

Noncooperative 802.11 MAC Layer Fingerprinting and Tracking of Mobile Devices

Expertise Centre for Digital Media, UHasselt-tUL-imec, Wetenschapspark 2, 3590 Diepenbeek, Belgium

Correspondence should be addressed to Pieter Robyns; eb.tlessahu@snybor.reteip

Received 5 January 2017; Accepted 21 March 2017; Published 25 May 2017

Academic Editor: Pascal Lorenz

Copyright © 2017 Pieter Robyns et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We present two novel noncooperative MAC layer fingerprinting and tracking techniques for Wi-Fi (802.11) enabled mobile devices. Our first technique demonstrates how a per-bit entropy analysis of a single captured frame allows an adversary to construct a fingerprint of the transmitter that is 80.0 to 67.6 percent unique for 50 to 100 observed devices and 33.0 to 15.1 percent unique for 1,000 to 10,000 observed devices. We show how existing mitigation strategies such as MAC address randomization can be circumvented using only this fingerprint and temporal information. Our second technique leverages peer-to-peer 802.11u Generic Advertisement Service (GAS) requests and 802.11e Block Acknowledgement (BA) requests to instigate transmissions on demand from devices that support these protocols. We validate these techniques using two datasets, one of which was recorded at a music festival containing 28,048 unique devices and the other at our research lab containing 138 unique devices. Finally, we discuss a number of countermeasures that can be put in place by mobile device vendors in order to prevent noncooperative tracking through the discussed techniques.