Automobile companies have competed fiercely to create the best autonomous car technology. Autonomous cars utilize operating systems, which creates some cyber-security concerns for the safety of the passengers. Unfortunately, such concerns have not been thoroughly studied in the literature. We develop a game-theoretical model to demonstrate strategic interactions between an autonomous car’s operating system and a hacker. Then we analyze their trade-offs by using Nash equilibrium. The framework provides some robust attack and defense strategies against the worst-case scenario in cyber-security. We provide an initial approach for the effective decision-making development of operating systems in autonomous cars for real-life.