A maintenance window should close
Remote support is useful when access has a known person, a specific purpose and a defined end.
In 30 seconds
- Verify the technician through an established contact, not only an incoming message.
- Use an approved access route, individual accounts, minimum privileges and MFA where supported.
- Approve the time window, supervise or log the session, and revoke temporary access when the work ends.
Make it concrete
A technician asks for permanent access to avoid calling next time. Compare this with a renewed, recorded approval for each maintenance job.
- 01Approve
- 02Observe
- 03Revoke
Check your understanding
Does a VPN automatically justify unrestricted access to every OT system?
- Verify the technician through an established contact, not only an incoming message.
- Use an approved access route, individual accounts, minimum privileges and MFA where supported.
- Approve the time window, supervise or log the session, and revoke temporary access when the work ends.
Go to the source
- Course notes · Nguyễn Văn Thư · An ninh mạng và khả năng chống chịu an ninh mạng trên tàu biển ↗
- CISA · Managing Remote Access for Industrial Control Systems ↗
Sources reviewed: 13.09.2026