Bluetooth Devices Can Covertly Track Mobile Users

Over the past few years, mobile devices have become extremely useful in engaging users for streaming and other purposes over the Bluetooth Low Energy (BLE) protocol and this is a significant privacy risk.

Indeed, a new research study investigates how your smartphone or laptop gives off unique Bluetooth radio signals that can be identified and used to track your device's location.  

Using Bluetooth signals generated by smartphones, security researchers at the University of California San Diego have developed a method of identifying and tracking users via their smartphones.

“Mobile devices increasingly function as wireless tracking beacons. Using the Bluetooth Low Energy (BLE) protocol, mobile devices such as smartphones and smartwatches continuously transmit beacons to inform passive listeners about device locations for applications such as digital contact tracing,” says the University’s research report .

“The mobile devices we carry every day, such as smart- phones and smartwatches, increasingly function as wireless tracking beacons. These devices continuously transmit short- range wireless messages using the Bluetooth Low Energy (BLE) protocol.”

During the team’s research they discovered that Bluetooth signals, which are continuously being sent by phone, have a unique fingerprint that can be identified.

In addition, they also raised concerns that hackers could exploit this technology in order to track the locations of a target. As a result of this new technique, the current safeguards against telephone stalking could be bypassed easily.

Bluetooth is becoming more and more of a problem in the modern world because it is not only a wireless signal that emits a multitude of signals but also an ongoing one that is emitted continuously from smart devices. WiFi and other wireless technologies are used to do wireless fingerprinting, and this is not a new concept. In all three cases, a WiFi signal depends on its preamble to perform the operation.

Due to the very short preamble of Bluetooth beacons, this technique has historically been unable to provide accurate fingerprinting results.

As a result of this new technique, Bluetooth beacons can be tracked and the unique fingerprint of a target device can be identified. As part of their experiments, the researchers have tested out this new tracking method in real-world situations as well. Initial experiments were conducted on a small scale, where 40% of the total number of mobile devices (162) found in a public area were uniquely identified.

There are many smartphones and other devices that can be targeted by such an attack. A typical attack of this kind will require around $200 worth of equipment and can be conducted on a wide range of gadgets.

In addition, the researchers noted that even when Bluetooth is turned off on a device, the device would emit Bluetooth beacons regardless. In order to stop the beacon from being broadcasted, the beacon itself must be turned off.

The Bluetooth hacks that have been made public in recent months have also exposed a number of other high-profile attacks.The NCC Group findings on BLE hacks in May led researchers to conclude that criminals might be able to unlock and steal Tesla cars if they were using this hack. What this means is that if we have our Bluetooth constantly on and constantly broadcasting, we need to be aware what other apps on our phone are using this information, what permissions they have been granted and how this could benefit commercial tracking which uses Bluetooth technology.

It's likely that you might be able to disable Bluetooth signal "beaconing" by turning off Find My in your Apple account. But that takes away one of the benefits of owning an Apple device. 

Ultimately, the researchers conclude that tracking people via BLE can be done, and some people are more vulnerable than others, depending on conditions and the commonness or uniqueness of the device targeted.

UC San Diego:     BLEMobileApps:    Privacy International:     Cybersecurity News:   

Quora:     Toms Guide:    The Register: 

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