Intelligent Transport Systems (ITSs) are part of road transportation sector evolution and constitute one of the main steps towards vehicle automation. These systems use technologies that allow vehicles to communicate with each other or with road infrastructure. By increasing information quality and reliability, ITSs can improve road safety and traffic efficiency, but only if cybersecurity and data protection is ensured. With the increase in the number of cyberattacks around the world, cybersecurity is receiving increased attention, especially in the area of transportation security. However, it is equally important to examine and analyze security in depth when it concerns connected vehicles. In this paper, we propose a qualitative risk analysis of ITSs based on Threat, Risk, Vulnerability Analysis (TVRA) methodology, and we focus on ETSI ITS communication architecture. We present a review of solutions and countermeasures for identified critical attacks.