Illustrative example
HypotheticalA firewall rule is opened for a historian upgrade. The change record sets an expiry date, and verification after the upgrade confirms the rule was removed.
“Changes to logic and configurations happen without a security check or record.”
Know what changed, why, and who approved it
Uncontrolled changes are a common cause of both security gaps and operational incidents. A lightweight security review keeps changes fast while keeping them visible.
Why it matters
Hidden exposure
A temporary rule or connection can become permanent.
Stale records
Inventories and drawings drift when changes aren't recorded.
Incident response
Responders need to know what changed recently.
Compliance
Change control is required by most OT frameworks.
A structured approach
A sequence that can be adapted to your environment and scope.
Request
Capture the change, affected assets and reason.
Review
Answer security impact questions for the change type.
Approve
Route to the right owner, including emergency changes.
Verify
Confirm the result and remove temporary measures.
Update
Update inventory, drawings and risk records.
What you end up with
- Security-reviewed change records
- Up-to-date asset and architecture data
- Emergency change follow-up
- An audit trail for reviews
Frequently asked questions
Does OT change control slow down maintenance?
It shouldn't. A short set of security questions per change type, with a defined emergency path, adds minutes rather than days.
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