This class of hack is known as a relay attack, a close cousin of the person-in-the-middle attack. In its simplest form, a relay attack requires two attackers. In the case of the locked Tesla, the first attacker, which we’ll call Attacker 1, is in close proximity to the car while it’s out of range of the authenticating phone. Attacker 2, meanwhile, is in close proximity to the legitimate phone used to unlock the vehicle. Attacker 1 and Attacker 2 have an open Internet connection that allows them to exchange data.