Access & Assurance
Secure Remote Access to OT
Control the access path, not only the user account
Strong identity is essential, but secure OT remote access also depends on device posture, controlled pathways, approval, session visibility and operational ownership.
Identity is only one layer
Multi-factor authentication and privileged accounts are important, but they do not fully address the risk of an unmanaged supplier laptop, an over-privileged session or a direct connection to a control asset.
OT remote access should be designed as an end-to-end access path.
Use a controlled access architecture
Access should pass through approved entry points such as a secure access service, jump host or privileged access platform. Direct exposure of controllers, HMIs or engineering systems should be avoided.
The architecture should also separate administrative access from normal operational traffic.
Constrain privilege and time
Users should receive only the access required for the approved task and only for the required period. Approval and just-in-time controls can reduce standing access and make exceptional activity visible.
Shared accounts and persistent vendor access make accountability and investigation more difficult.
Address device trust
Where the organisation cannot manage the supplier device, the access design should reduce reliance on that endpoint. Options may include browser-based sessions, virtual workspaces, controlled file transfer, malware scanning and restrictions on clipboard or drive mapping.
The appropriate control set depends on the operational task and system sensitivity.
Make sessions observable
Privileged activity should be logged and, where appropriate, recorded. Alerts may be required for unusual timing, access outside an approved scope, unauthorised tools or unexpected changes.
Session evidence supports both real-time response and later review.
This article provides general advisory commentary. It does not identify any client, employer or specific operational environment and should not be treated as legal, regulatory or system-specific advice.
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