CISA, Australia and partners issue guidance to isolate operational technology and supporting systems in critical infrastructure

The Cybersecurity and Infrastructure Security Agency, alongside the Australian Signals Directorate, the United Kingdom’s National Cyber Security Centre, and the Canadian Centre for Cyber Security, has released joint guidance aimed at helping operators of critical infrastructure keep essential services running during major cyber incidents or geopolitical crises.

Titled CI Fortify – Advice for Isolating Vital Systems and led by ASD, the document focuses on practical measures to segment and, when necessary, isolate operational technology environments to prevent or contain attacks and speed recovery. The agencies say state-sponsored actors increasingly target critical infrastructure to conduct espionage or disrupt services, particularly amid broader geopolitical tensions.

“America’s critical infrastructure is frequently targeted by malicious state-sponsored cyber threat actors whose aim is persistent access to vital systems and disrupt essential services such as telecommunications, water, energy, and transportation. As part of our CI Fortify Initiative, CISA, with our partners, provides this timely, collaborative resource that helps critical infrastructure ensure resilience during a crisis,” said Acting Executive Assistant Director for Cybersecurity Chris Butera. “CISA urges OT owners and operators to maintain robust isolation and recovery plans so that essential services can continue under degraded conditions, enabled through either manual or alternative SCADA paths. Through proactive planning and practice, we can strengthen critical infrastructure defenses against state-sponsored threat actors.”

The guidance emphasizes preparation for sustained, independent operations if nationwide disruptions affect supply chains or interconnected systems. It outlines how organizations can identify critical assets and dependencies, map connections, and design separation points that allow facilities to continue functioning safely in isolation.

According to the agencies, the document covers:
– Methods to identify and map vital systems and their connections
– How to build and validate effective separation points
– Graduated isolation planning, including drills and regular testing
– Case examples illustrating resilience during ransomware events

CI Fortify – Advice for Isolating Vital Systems is available at: https://www.cisa.gov/resources-tools/resources/ci-fortify-advice-isolating-vital-systems