�In recent events, cyber attacks have been part of hybrid warfare. NATO and its Allies rely on strong and resilient cyber defences to fulfil the Alliance’s core tasks of collective defence, crisis management and cooperative security. NATO needs to be prepared to defend its networks and operations against the growing sophistication of the cyber threats and attacks it faces.� (NATO Cyber Defence, 2018) The complexity of Cyberspace, its vast area of applications and the terminology adopted by both the Modelling and Simulation (M&S) and Cyber Community of Interest, make it difficult from both sides to achieve a comprehensive understanding on how M&S could support the Cyber Domain. This paper proposes a holistic approach to better clarify the areas of application of state-of-the-art M&S technology in Cyberspace. Applying the NATO Concept Development & Experimentation methodology, the authors have developed a research phase, investigating possible solutions to implement a Modelling and Simulation as a Service environment to support and improve NATO’s and Nations’ efforts in the development of Cooperative Cyber Capabilities. In particular, this research focuses on the NATO Cyber Range Capability development and implementation, looking at improving and expanding its technical capabilities in a distributed cooperative environment through Cyber-based M&S services, namely the Cyber Synthetic Services (CyS2). The result of this research activity is a Live-Virtual-Constructive simulation technology concept suitable to support studies and further research activities, focusing on use-cases related to the effects of Cyber threats against C2/C4ISTAR systems, Unmanned Autonomous Systems and Operational Technology like Supervisory Control and Data Acquisition systems. The CyS2 solution could potentially support any NATO or National organization dealing with the Cyberspace, and it could be considered a technical baseline for the implementation of a future NATO Cyber Synthetic Environment.