Bluetooth users beware: Hackers can track the location of your Apple & Microsoft devices

Researchers uncover security flaw in state-of-the-art smartphones, wearables, workplace essentials & more.

By Molly Gluck

Bluetooth technology is everywhere — ranging from smart phones, to wearables, to connected home devices. Wearables are also infiltrating the workplace: according to a PwC report, more than 75 million wearables will permeate businesses across all industries by 2020.

Despite the countless benefits of Bluetooth technology, the widespread adoption of these devices into our daily lives comes along with security risks. David Starobinski and Johannes Becker, researchers from Boston University, uncovered that popular Bluetooth devices including iPhones, iPads, Apple Watches and FitBits — and workplace essentials including MacBooks and Microsoft tablets and laptops — have a flaw that exposes device users to the risk of being tracked by unwanted adversaries.

We spoke with the researchers to learn more about how Bluetooth devices can be tracked, the implications of this discovery, and best-practices for protection in the Q&A below.

1) What is the difference between Bluetooth and BT LE? Why has Bluetooth become so ubiquitous?

Bluetooth technology is increasingly facilitating the ubiquity of instant wireless connectivity — ranging from personal connected accessories, to smart homes, to workplace productivity, wellness and communication enhancements. This has led to a remarkable number of 4.2 billion Bluetooth-enabled devices to day — projected to be 5.2 billion by 2022.

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2) How does Bluetooth technology work?

  • Imagine a Bluetooth beacon installed in the shirts area of a department store broadcasting the equivalent of “Hi, this is the shirts aisle at Department Store Location XYZ” to enable location-based information to pop up on the store’s app.
  • Or, picture your fitness tracker saying the equivalent “Hi, I’m smart watch ABC123” so that your smartphone can connect to it as soon as they come in range of each other, without having to search for it.

3) What makes Bluetooth devices vulnerable? Which devices are vulnerable?

We took a closer look at state-of-the-art devices that do in fact use address randomization, such as Windows 10, iOS, and macOS devices. As it turns out, the content of their advertising messages often contains unique data that doesn’t change when the address is randomized again. We call these contents “identifying tokens” and use them to basically jump from one random address to the next — effectively tracking a device beyond what the manufacturer has chosen as an address lifetime.

4) Why are manufacturers developing and distributing devices with these vulnerabilities?

However, this vulnerability does not only stem from cutting corners. Privacy-preserving optimizations complicate the design and sometimes create usability issues for manufacturers — specifically, accessories that employ address randomization may more easily disconnect. Some manufacturers avoid these optimizations altogether, while others try to find a proper balance. In the context of our research, the Apple and Microsoft manufacturers were not cutting corners. These Windows 10, iOS, and macOS devices did have privacy protecting measures implemented — yet the complexity of Bluetooth technology left privacy and security gaps in these protection measures.

5) In light of these vulnerabilities, what are the risks for consumers, businesses, and government?

In the context of Bluetooth devices, the government and business-level privacy concern is elevated by the realistic feasibility of BLE-based botnets and complementary threats such as large-scale tracking of users via compromised Wi-Fi routers, which amplify trackability to a global scale.

On the consumer-level, electronic purchase transactions, facial recognition and other digital traces could be combined with Bluetooth tracking to generate a fine-grained location profile of a victim.

6) How can we protect ourselves?

To protect their employees and information, businesses could consider it holding a wearables training before giving out FitBits for an employee fitness challenge — or providing a quick overview of best-practices for privacy before giving an employee a work-related mobile phone, tablet or computer.

To limit — and communicate — the vulnerabilities and risks associated with their devices, manufacturers are incentivizing security researchers to uncover submit security flaw findings in order to better secure their devices. These three practices are all valuable and effective first-steps in the journey toward better securing Bluetooth technologies.

For additional commentary by Boston University experts, follow us on Twitter at @BUexperts. You can follow Boston University College of Engineering at @BUCollegeofENG on Twitter.

Cutting-edge research and commentary out of Boston University, home to Nobel laureates, Pulitzer winners and Guggenheim Scholars. Find an expert:

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