Hacking Bluetooth, a wireless voice and data transmission technology, which can be found in mobile phones, PDAs, USB sticks, keyboards, mices, headsets, printers, telephone facilities in cars, navigation systems, new modern advertisement posters, umbrellas, basket, socker and golfballs, and fridge magnets.
The design of Bluetooth pays a lot of attention to security. The connection can be encrypted and authenticated. The address is set by the device firmware and not by the OS kernel, which makes address spoofing harder but not impossible.
A device can be set into non-discoverable mode for it to not show up in a scan result.
The protocol stack is so complex that various vulnerabilities have come up in all common Bluetooth implementations like Android, iOS, Windows and Linux.
It is now common for radioing devices to appear in the craziest places.