Our research revealed several weaknesses in the Tesla Model S passive keyless entry and start system. The talk will be a comprehensive overview of how we reverse engineered the key fob, the issues we found and an efficient proof of concept attack. The proof of concept attack exploits the use of an inadequate cipher and allows us to clone a Tesla Model S key fob in a matter of seconds using commercial off-the-shelf hardware. Information from the FCC database suggests that the same attack could affect vehicles produced by McLaren, Karma and Triumph Motorcycles as they all use a passive keyless entry and start system designed by Pektron. I will share our experience with responsibly disclosing our findings with all the manufacturers.