This paper presents a novel simulation for estimating the impact of cyber attacks. Current approaches have adopted the probabilistic risk analysis in order to estimate the impact of attacks mostly on assets or business processes. More recent approaches involve vulnerability analysis on networks of systems and sensor input from third-party detection tools in order to identify attack paths. All these methods are focusing on one level at a time, defining impact in terms of confidentiality, integrity, and availability, failing to place people and technology together in an organization’s functional context. We propose an interdependency impact assessment approach, focusing on the responsibilities and the dependencies that flow through the supply chain, mapping them down into an agent-based socio-technical model. This method is useful for modeling consequences across all levels of organizations networks—business processes, business roles, and systems. We are aiming to make chaining analysis on threat scenarios and perform impact assessment, providing situational awareness for cyber defense purposes. Although the model has various applications, our case study is specifically focusing on critical information infrastructures due to the criticality of the systems and the fact that the area is still lacking security-focused research and heavily relies on reliability theory and failure rate.