Section: New Results

Wi-Fi and privacy

Participants : Cédric Lauradoux, Mathieu Cunche, Levent Demir.

Active service discovery in Wi-Fi involves wireless stations broadcasting their Wi-Fi fingerprint, i.e. the SSIDs of their preferred wireless networks. The content of those Wi-Fi fingerprints can reveal different types of information about the owner. In [5] , we focus on the relation between the fingerprints and the links between the owners. Our hypothesis is that social links between devices owners can be identified by exploiting the information contained in the fingerprint. More specifically we propose to consider the similarity between fingerprints as a metric, with the underlying idea: similar fingerprints are likely to be linked. We have studied the performances of several similarity metrics on a controlled dataset and then apply the designed classifier to a dataset collected in the wild. Our study is based on a dataset collected in Sydney, Australia, composed of fingerprints belonging to more than 8000 devices.

Extending this problem, we present a set of attacks that allow an attacker to link a Wi-Fi device to its owner identity. We present two methods that, given an individual of interest, allow identifying the MAC address of its Wi-Fi enabled portable device. Those methods do not require a physical access to the device and can be performed remotely, reducing the risks of being noticed. We present in [4] , [35] scenarios in which the knowledge of an individual MAC address could be used for mischief.