If you don't want anyone to know how badly you missed your exercise goals this week, the Acer Liquid Leap is not the fitness tracker for you; and the FitBit Charge isn't much better. According to research released today by AV-TEST, while most fitness trackers succeeded at transmitting users' data to the cloud securely, some brands failed badly at locking down communications between the wristband devices and the smartphone apps.
AV-TEST examined nine different trackers: the Acer Liquid Leap, FitBit Charge, Garmin Vivosmart, Huawei TalkBand B1, Jawbone Up24, LG Lifeband Touch FB84, Polar Loop, Sony Smartband Talk SWR30, and Withings Pulse Ox.
Of those, the Sony Smartband Talk was the lowest-risk -- with the only complaint being that users could not deactivate Bluetooth on the wristband device -- followed by the Polar Loop.
The one with the "highest probability of a successful attack" is the Acer Liquid Leap. (It's a product that Acer simply bought and sold with its own label on it, unmodified, so it is identical to products sold under other names, including the Striiv Touch, Tofasco 3 Plus Swipe, and Walgreens Activity Tracker. As AV-TEST points out, "It is not clear, however, whether the other vendors have modified the app and the firmware of the wristbands.")
Among the complaints: Bluetooth cannot be deactivated on the Acer wristband; the wristband would "pair" with a smartphone without requiring any confirmation; the wristband can be used by several smartphones at once; the app does not use code obfuscation, and; the app reveals log data.
Second-worst was the FitBit Charge. It has many of the same failings as the Acer, but what researchers were particularly struck by was that the wristband wasn't at all picky about who it shared data with.
"The fitness wristband FitBit Charge astonished the test engineers: Any smartphone with Bluetooth is welcome to the fitness tracker. It does not prompt for a PIN or other authentication – it simply connects and voluntarily hands over all its data. The data is not even encrypted or protected in other ways," AV-TEST said it in its report.
By comparison, the Sony Smartband Talk connects to smartphones automatically, but only with known, trusted devices. And although Bluetooth cannot be disabled on the Sony wristband, it does become invisible once it pairs with a device.
Why the cause for concern? "In the United States, for example, those who demonstrate good fitness using the tracker are eligible for lower premiums on their private health insurance. What would keep people from simply using the data of their neighbor of the same age with a much higher level of fitness? Those familiar with what people pay for health insurance in the United States know how great the criminal potential may be in this area," the report said.
Data manipulation could also be used for more personal attacks on fitness tracker users: "And if trackers can be manipulated, it won't be long before kids will be playing pranks on the jogging yuppie by increasing his blood pressure and pulse data by a few notches ... The current test indicates: the potential attack points are more than sufficient."