More and more functionality that demands remote access on a vehicle is in-tegrated into modern cars. Fleet management, infotainment, updates-over-the-air and the upcoming functionality for autonomous driving need gate-ways that enable a car-2-x communication. Misuse is a threat. Consequently, security mechanisms play an increasing important role. But how can we show and prove the effectiveness of these security functions? Therefore, in this paper we will show an approach to test security aspects, based on virtual instrumentation. The approach is to use a framework that executes the application under development on a virtual model of the target micro controller. An interception library generates scenarios systematically, whereas the effects on registers and memory are monitored. We are inter-cepting the running software at vulnerable functions and variables to detect potential malfunctions. This will detect security vulnerabilities of all internal failure even if no malicious behavior at the interfaces occur.