National Institute of Standards and Technology (NIST) maintains one of the most widely adopted cyber security frameworks for critical infrastructure. NIST Cyber Security Framework is a system to base the creation of policies and procedures on for the purposes of managing risk, security hardening networks, and incident response. There is a lot of content in the Framework, designed to cover a lot of ground.
The Cyber Security Framework consists of three main components: The Core | Implementation Tiers | and Profiles. The Framework Core provides a set of desired Cyber Security activities and outcomes using common language that is easy to understand. The Core guides organisations in managing and reducing their cyber secuirty risks in a way that complements an organisations existing cyber security and risk management processes.