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  • Author: Mathieu Cunche x
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Discontinued Privacy: Personal Data Leaks in Apple Bluetooth-Low-Energy Continuity Protocols

Abstract

Apple Continuity protocols are the underlying network component of Apple Continuity services which allow seamless nearby applications such as activity and file transfer, device pairing and sharing a network connection. Those protocols rely on Bluetooth Low Energy (BLE) to exchange information between devices: Apple Continuity messages are embedded in the pay-load of BLE advertisement packets that are periodically broadcasted by devices. Recently, Martin et al. identified [1] a number of privacy issues associated with Apple Continuity protocols; we show that this was just the tip of the iceberg and that Apple Continuity protocols leak a wide range of personal information.

In this work, we present a thorough reverse engineering of Apple Continuity protocols that we use to uncover a collection of privacy leaks. We introduce new artifacts, including identifiers, counters and battery levels, that can be used for passive tracking, and describe a novel active tracking attack based on Handoff messages. Beyond tracking issues, we shed light on severe privacy flaws. First, in addition to the trivial exposure of device characteristics and status, we found that HomeKit accessories betray human activities in a smarthome. Then, we demonstrate that AirDrop and Nearby Action protocols can be leveraged by passive observers to recover e-mail addresses and phone numbers of users. Finally, we exploit passive observations on the advertising traffic to infer Siri voice commands of a user.

Open access
Privacy-preserving Wi-Fi Analytics

Abstract

As communications-enabled devices are becoming more ubiquitous, it becomes easier to track the movements of individuals through the radio signals broadcasted by their devices. Thus, while there is a strong interest for physical analytics platforms to leverage this information for many purposes, this tracking also threatens the privacy of individuals. To solve this issue, we propose a privacy-preserving solution for collecting aggregate mobility patterns while satisfying the strong guarantee of ε-differential privacy. More precisely, we introduce a sanitization mechanism for efficient, privacy-preserving and non-interactive approximate distinct counting for physical analytics based on perturbed Bloom filters called Pan-Private BLIP. We also extend and generalize previous approaches for estimating distinct count of events and joint events (i.e., intersection and more generally t-out-of-n cardinalities). Finally, we evaluate expirementally our approach and compare it to previous ones on real datasets.

Open access