In Cooperative Intelligent Transportation Systems (C-ITS), vehicles can communicate with one another and with the infrastructure. The openness of the transportation system to new functionalities and use cases may create new vulnerabilities that must be taken into account. In this paper, we study three main use cases, the effectiveness and performance evaluation of certificate reloading in real environment (while driving), the privacy evaluation of pseudonym certificates change strategies by proposing an attacker model on real exchanged messages, and finally, we implement Sybil and data replay attacks to test our misbehavior detection solution.