As cars are increasingly connected and autonomous, they also become more exposed to cyber security threats. Providing strong protection and reactive response to such threats in a large industry involving many tiers and complex safety critical systems is challenging and required the development of the new ISO 21434 standard. Along with ISO 2626 dedicated to safety, it provides solid grounds for safety-security co-engineering. This paper focuses on how to provide effective and efficient support to the risk assessment phase based on a model-based approach. A rich goal-oriented meta-model is proposed to capture automotive assets and system properties, to estimate the impact of damage scenarios, to identify threats and to assess their feasibility. The approach is implemented as proof-of-concept through the meta-model adaptation of a generic co-engineering platform and is illustrated on the car light control sub-system.