Attacks over Bluetooth require an attacker hacker to be within metres of a target device. This malware can be delivered 10 seconds after devices connect, making even fleeting proximity a problem. Testing the success of the hack takes about a minute, although it is unnecessary for the compromise.
So, attack a Fitbit via Bluetooth which then jumps to any computer(s) you attach it to.
It would then need to be that the code gets executed in some way and, of course, that hole exploited thereafter. But still a pretty interesting way to get to a person’s computer.
/via Bruce Schneier.