OT Cybersecurity Checklist (ISA/IEC 62443) for 2026

Most OT incidents exploit basic control gaps: unclear ownership, weak remote access controls, and poor change management. This checklist focuses on controls you can implement quickly with measurable impact.

Governance and Ownership

• Assign named owners for OT risk, incident response, and patch decision authority.
• Maintain an asset inventory with criticality tags for all control network components.

Access and Segmentation

• Enforce MFA for all remote OT access pathways.
• Segment Level 2/3 networks and restrict east-west traffic by allowlist rules.
• Remove shared admin accounts and rotate privileged credentials on a fixed schedule.

Operational Controls

• Run quarterly restore tests for SCADA and historian backups.
• Track security patches with explicit defer/accept decisions and business sign-off.
• Drill incident response playbooks with operations and maintenance teams.

Start with the top 10 critical assets and execute this checklist within 60 days. Scope control and repeat cadence are more important than one-time broad audits.