As critical infrastructure sectors face escalating cyber and physical threats as they digitally transform, it is essential to implement robust security strategies. Recognizing the unique challenges and architectures in securing these environments, the Cloud Security Alliance (CSA), an organization that defines standards, certifications, and best practices for ensuring a secure computing environment for enterprises, issued Zero Trust Guidelines for Critical Infrastructure. This guidance explores the critical and rigorous application of Zero Trust (ZT) principles within operational technology (OT) and industrial control systems (ICS).
This paper, developed by CSA's Zero Trust Working Group, establishes the basic concepts of Zero Trust and provides a personalized roadmap for effectively implementing these principles in OT/ICS settings. The research uses the recommended, repeatable, five-step CSA process for Zero Trust: defining the protection surface (the area that the ZT policy will protect), mapping operational flows, establishing the Zero Trust architecture, creating Zero Trust policies, and monitoring and maintaining the network.
This process, originally outlined in the NSTAC Report to the President on Zero Trust and Trusted Identity Management, represents best practices for handling Zero Trust projects, and with it, organizations can effectively mitigate risks and enhance their CI resilience.
“The Zero Trust strategy is a powerful way to fortify critical operating systems/industrial control systems against increasingly sophisticated adversaries as they can keep up with rapid technological advances and an evolving threat landscape,” said Jennifer Minnella, lead author of the study and a member of the research team. Zero Trust Working Group Leadership Team. “We hope that this set of guidelines will serve as a useful tool for communication and collaboration between those teams charged with cybersecurity policies and controls and the owners and operators of operational and industrial control systems.”
Specifically, the document provides a detailed examination of the inherent differences between traditional IT systems and ICS/ICS, focusing on aspects such as network design, hardware heterogeneity, and specific security requirements. Additionally, it provides a step-by-step implementation guide with actionable insights for each stage of deploying the ZT model in these unique settings. This includes specific guidance on identifying critical assets, mapping data flows, creating a custom ZT architecture (ZTA), policy formulation, and the nuances of continuous monitoring within an OT/ICS context.
“In an environment where security is both critical and clearly a challenge, Zero Trust is not just a security upgrade but a necessity. By identifying practical strategies and specific methodologies designed to implement a Zero Trust strategy in CI environments, we help ensure resilience and security amidst fast-paced digital technology.” Evolution and threat landscape from the Zero Trust Working Group leadership team.
