Detecting Malicious Bluetooth Trackers

There’s new research from University of Washington on BLE-Doubt: Smartphone-Based Detection of Malicious Bluetooth Trackers University of Washington (PDF).

Stalkers can hide Bluetooth beacons on targets’ clothing or in vehicles so as to monitor their locations. The researchers created an open-source method of detecting maliciously deployed Bluetooth beacons.

The algorithm detects malicious devices within a few minutes. The software scans for Bluetooth advertisements and stores a history so that an alert can be created if a beacon is following the same route as the user.

iBeacon, Altbeacon, Eddystone, Tile, Chipolo, Spot, and AirTag are all detected with AirTags the greatest challenge due to rotation of their MAC addresses between every two hours and once a day and their erratic and unpredictable advertising.

The app doing the scanning causes heavy smartphone battery use. The smartphone lost between 5% and 10% of its battery per hour during active scanning.

View Tracker Beacons

Do You Have a Beacon That Makes a Sound When You Are Near?

The quick answer is no.

The longer answer is that beacons don’t know if anyone is near because they are not doing the listening. They just send out information. It’s possible to have a smartphone app see the beacon and the phone make a sound.

F6 Tracker Beacon

We also have special tracker type beacons to which an app can connect rather than just detect. Once connected, the app can cause the beacon to ring. However, only one app user can connect at a time.

New Minew F6 Tracker Beacon

We have the new Minew F6 Tracker Beacon in stock.

F6 Tracker Beacon

Tracker beacons are different from normal beacons in that they are designed to be connected to an app for the majority of the time. Non-tracker beacons just advertise and aren’t usually connected except for setup.

The F6 comes with iOS and Android SDKs that provide for bonding/pairing with a password, listening to events such as connecting, connected, disconnected, getting the MAC address and RSSI, ringing the tracker, receiving a button press event, receiving a notification n seconds after disconnect and disconnecting at a given distance (received signal power level, RSSI).

View Tracker Beacons

Changing the Battery in the F4 Tracker Beacon

We recently started selling the Minew F4, a quality tracking beacon with external on/off button, 85dBm buzzer and range of up to 50m. The battery last about 6 months. Minew have a video how to change the battery:

There’s a T-Finder iOS and Android app on the app stores but the intention is that this beacon will be used with your own apps and solutions using the supplied Android and iOS SDK.

View Tracker Beacons

Apple Tag – a Tile-like Device

In our previous post on Apple WWDC on the ‘Find my’ feature we explained how the use of others’ phones for finding your devices is much like Tile (and other tracking beacons). However, there’s evidence that Apple might also be creating their own, separate, Tile-like device. 9to5Mac also have some further speculations.

It’s also interesting that Apple are changing the API for looking for beacons. CLBeaconRegion has become CLBeaconIdentityConstraint. The functionality currently remains the same in that you can filter by UUID/major/minor. However, the renaming of the API to make it more generic suggests it might eventually also be used for something else which might be the Apple tag.

While devices such as the Tile are great, when finding items remotely, they assume lots of people have them for someone else’s Tile app to see your tile. While the Tile network is large at 15 million trackers it will never be large enough to reliably find things. Apple has a much greater reach to make such a scheme more successful. Tracking things such as your lost car or dog become far more feasible.

An observation is that Google Android has a substantially greater reach offering Google the opportunity to offer something similar, more reliable (due to sheer number of devices) but more open as they did with Bluetooth Eddystone vs iBeacon. Taking this idea further, it’s a shame there isn’t an open Bluetooth tracking system or standard, for example, championed by the Bluetooth SIG.

September 2019 Update: It’s looks like Apple will be using UWB rather than Bluetooth making the solution more accurate and more proprietary. If true, it will eventually compete with Bluetooth Direction Finding.

May 2020 Update: The device will be called AirTag.

Tracker Beacons Now In Stock

We now have some tracker Bluetooth beacons in stock. Tracker beacons are Bluetooth beacons designed specifically for tracking physical items or remote camera button-type applications but they can be used for other purposes. Unlike iBeacon, Eddystone and Sensor beacons, there’s no configuration app, the Bluetooth advertising data is fixed and can’t be re-configured.

Tracker beacons differ from (most) iBeacons in that they, once connected via Bluetooth GATT, allow the beacon to ring, can detect a beacon button press and the beacon can ring when it goes out of range.

Tracker beacons can also be used, without GATT connection, to detect presence by using their MAC address on Android/gateways, or peripheral id on iOS CoreBluetooth, to uniquely identify them.

There are many poor quality tracker beacons on the market that are unreliable. It has taken us a while to find quality tracker beacons that also have known Bluetooth Services/Characteristics for programming purposes.