Ever wondered how secure you are with a fitness tracker on your wrist? The researchers at Open Effect have... and their answer is "not as much as you'd probably like." In their analysis, several common trackers have flaws that theoretically let attackers follow you or intercept data. Seven out of eight used static hardware identifiers that could allow location tracking over Bluetooth, for a start. Also, the companion apps from Garmin, Jawbone, Withings and Xiaomi have holes that not only expose data, but let evildoers fake fitness info -- a problem in lawsuits where that data could be crucial evidence.