Today's vehicular systems comprise complex and distributed structures and encompass in some cases more than 70 Electronic Control Units (ECUs). In the near future the number of electronic components will further increase and more and more vehicular functions will be implemented in hard- and software. However, for this reason the threat potential for those systems increases significantly. In order to make use of the IT penetration for OEMs, suppliers, repair shops, service providers etc., the security of the deployed technologies is an indispensable requirement.