Remote car hacking is very hard but it is not entirely possible, testament to this is the previous car hack demonstrated on a Jeep Cherokee. At the DEFCON 23 hacker's conference, two researchers were able to hack into the information system of a Tesla Model S and was able to completely control the car remotely.
The hackers, Kevin Mahaffey and Marc Rogers, choose the Tesla Model S because they deemed the car to be the "archetype" of what cars will look like in the future. During their demonstration at DEFCON 23, the two hackers spent the first 40 minutes of their 50-minute talk explaining all the dead ends they encounter in hacking the Model S proving that the car indeed is equipped with top of the line security measures.
According to CNet, the two hackers first acquired the Model S through a private party and stripped its dashboard in order to know the ins and outs of the cars electronic map. Finally, they discovers two removable SD cars used for the cars file system and storing map data. They also found a set of diagnostic ports, a USB header and an enigmatic proprietary cable.
Following their discovery, the two hackers was able to access the cars firmware through the USB header only to be smacked with a dead end since the firmware was secured and was unhackable. Hidden deep into one of the SD cards, the hackers found out that the car's dashboard software has the QtWebKit version which was previously exploited in order to hack the PS Vita handheld console. They thought they have found a way in, only to find out that Tesla was able to patch the browser and was totally secured from hacking.
The first piece of the puzzle was found on the same SD card which contains the file named carKeys.tar which has a set of digital keys used to start the car when the keyless entry transponder is in range. The second piece of the puzzle was found in the previously mentioned proprietary cable which gave the hackers access to the cars onboard network by creating an adapter out of scotch tape and an Ethernet cable. Finally, the last piece of the puzzle was found hidden in the car's Wi-Fi connectivity which gave the hackers remote access to the car.
Despite their efforts, the two hackers claim that hacking the Tesla Model S is extremely hard. While it is possible, the car's information system is so secured that hackers will find it impractical to spend so match resources to conduct the hack.
In order to further improve their cars security, Tesla is offering a bug bounty. According to BugCrowd, Tesla is offering a bounty ranging from $25 up to $10,000 for any researchers that could point out flaws and bugs into its car's computer system.