CISA shares advice on isolating vital systems during cyberattacks
July 28, 2026 · BleepingComputer · Severity: CRITICAL
CISA, the Australian Cyber Security Centre (ACSC), the FBI, and international partners released 'CI Fortify — Advice for isolating vital systems,' urging critical infrastructure organizations to prepare plans for disconnecting OT from corporate and internet-facing networks during cyberattacks. The guidance covers identifying minimum systems for critical service delivery, documenting all connections, and determining isolation points. Strategies include physical isolation (most effective), graduated isolation (progressively restricting access), and data diodes (one-way data flow). State-sponsored actors (Volt Typhoon, Salt Typhoon) routinely target critical infrastructure. Organizations must test complete isolation plans, not just individual components, to uncover hidden dependencies.
Key Takeaways
- CISA urges OT isolation during attacks — New CI Fortify guidance recommends disconnecting vital OT systems from corporate and internet networks during cyber incidents.
- Three isolation strategies — Physical isolation (most effective), graduated isolation (progressive restrictions), and data diodes (one-way data flow devices).
- State-sponsored actors target infrastructure — Volt Typhoon, Salt Typhoon, and similar groups target water, energy, telecom, and transportation for espionage and disruption.