Days are not far off, when cars will be driving by themselves. Driverless cars or Autonomous vehicles are no more a fiction. Advanced Driver Assistance Systems (ADAS) has introduced lot of intelligence into car’s electronics. Cars can sense the surrounding, understand the scenario and take intelligent decisions. Cars can talk to other cars and exchange useful information. Cars can find out the best possible route to reach the destination. All this is made possible by tens of millions of lines of code running inside modern cars. Cars have been transformed to Cyber Physical Systems (CPS). They have more than hundred microcontrollers controlling all aspects of car from brake to steering to power windows. They are connected in various network topologies and are very complex. But, they are not secure. Researchers have already shown that, internal networks of modern cars are vulnerable to external attacks. Recent ransomware attacks have taken the IT world by storm. Attackers have used the known vulnerability in computer software to introduce ransomware, which will encrypt the hard-disk and then extract a ransom to decrypt it. The recent WannaCry ransomware could spread in a Local Area Network by making using of vulnerability in Windows SMB protocol. It was able to spread by itself and attack millions of computers all over the world in a matter of hours. If this is the situation in IT world presumed to be secure, what about insecure in-vehicle networks of automobiles? What if an attacker hacks a car and introduces ransomware? Will it be possible to hijack a fleet of vehicles by these hackers? Is automotive cyber security equipped to address these concerns? This paper discusses about the possibility of ransomware attack on automobiles and about possible ways to prevent such attacks.