The paradigm of the automotive industry has changed, over the course of the last10-15 years. Electronics and software, have introduced in many dierents parts ofa vehicle and the drive-by-wire it is taking over the vehicle functions. Connectivityfunctionalities are increasing in the context of the automotive industry as well. Allthe aforementioned parts have more than one common link. This thesis project willfocus on one of these links, which is the security. The focus will be the CAN busprotocol and specically, on investigating the implications of an adversary havingphysical access in a vehicle. An experiment will be contucted as part of this thesiswork, by using open source hardware (Arduino and Raspberry Pi) and a Man-inthe-middle (MITM) attack scenario, will be implemented. The application, whichwill perform the MITM attack (small scale CAN bus fuzzer) will be developedduring this project and it will be distributed as an open source software afterwards.