True auto safety can only be achieved by knowing what every piece of code and hardware is that goes into the car. The vulnerabilities that have come to light in the past four-to-five years are significant, but also generally harder to exploit for the average attacker. The need for a more significant operating system, and the need to have all these control units talk to each other, is at the heart of the modern day auto-hacking craze. There are some flaws that seem like a simple lack of foresight and how easy it can be to take advantage of simple workflows.
Source: https://threatpost.com/automotive-security-its-more-than-just-whats-under-the-hood/139987/