Note
After a vendor remote session: what to re-check
Remote support is how most plants keep specialised machines alive. It is also how rule engines, certificates, and “temporary” accounts enter production without a local signature.
The morning after a vendor session we ask operations to walk a one-page list with us or with their own engineer:
- Which accounts were created or unlocked, and were they locked again?
- Which flows, scripts, or dashboards show a modified time after the session started?
- Are there new retained messages on command topics?
- Did the device image hash change?
- Is the remote-access tool still running as a service?
- Did anyone screenshot the final configuration, or is the vendor’s memory the record?
If the answer to item 6 is the vendor’s memory, write down the configuration yourself before the next change. We have reconstructed “what the contractor did” from broker logs more than once; it is slower than a screenshot.
Sites that already run a permit-to-work system can hang this list on that permit. Sites that do not can still keep a paper folder. The audit finding is not that vendors exist. It is that the control application can change while everyone thinks they were only watching a trend.