Manufacturing teams should prioritise zero trust when remote support, cloud tools and plant systems are already interconnected enough that one connection can affect production. At that point, broad trust is no longer efficient, it is risky. Zero trust becomes the better fit because it narrows access by identity, device and session.
Why zero trust becomes the right threshold in manufacturing
Manufacturing teams should treat zero trust as the point solution once remote access is no longer a side channel but part of normal operations. When remote support, cloud tools and plant systems are connected enough that a single trusted path can influence production, legacy perimeter trust becomes too broad. The question is not whether remote access exists, but whether it can still be safely treated as inherently trusted.
That shift matters because manufacturing environments often blend IT, OT and third-party access. As those dependencies grow, the access model has to make fewer assumptions about network location and more about verified identity, device state and session context. NIST SP 800-207 Zero Trust Architecture is relevant here because it formalises that move from implicit trust to explicit verification.
Zero trust is most justified when the remote path can reach systems that matter to safety, uptime or production continuity. If a remote channel can alter recipes, configurations, historian data, engineering workstations or support tooling, then broad VPN-style trust is no longer just convenient, it is a production risk.
Where legacy remote access starts to fail
Legacy remote access models tend to trust the connection after the first login. That works only when the blast radius of any one session is small and the environment is tightly segmented. In manufacturing, that assumption breaks down as vendors, integrators, maintenance staff and cloud services all need different levels of access to the same operational estate.
The failure mode is usually excessive reach rather than a single dramatic misconfiguration. Once a user or service is on the inside, old models often allow lateral movement, broad protocol access or long-lived standing permissions. That is why manufacturing teams should also look at remote support workflows, not just user logins. NHIMG’s Remote Access Identity Guide is useful for mapping VPN replacement, device posture, third-party access and dormant remote accounts to the access paths that actually touch plant systems.
Remote access is also where trust failures compound over time. A model that is acceptable for occasional administrative access becomes fragile when it is reused for plant support, vendor maintenance and always-on operational monitoring. At that point, the access path itself becomes part of the control plane.
What zero trust changes for plant and vendor access
Zero trust changes the decision point from network membership to per-request policy. That means the access decision can consider who is connecting, from what device, to which asset, for what action, and for how long. In practice, that is what makes zero trust better suited to modern manufacturing estates than legacy remote access alone.
For plant and OT environments, the control value is often in reducing implicit reach. You do not need every remote user to see the full production network. You need narrowly scoped access that is time bound, attributable and tied to a specific support task. That is where the distinction between access and trust becomes operationally important. OT and ICS Identity and Access Guide helps frame vendor remote access, shared accounts and segmentation as part of the same control problem rather than separate issues.
For teams moving from legacy remote access, the important practical change is that zero trust is not just a replacement for VPN. It is a way to make remote access conditional, inspectable and easier to revoke. In manufacturing, that matters because production support often needs access that is legitimate but high impact.
Risk and Threat Considerations
Manufacturing remote access is attractive to attackers because it links external connectivity to systems that can stop or reshape production. The risk increases when the same access path is used by internal staff, suppliers and maintenance providers, because compromise of one credential or session can expose more than one operational segment.
Failure mechanism: Legacy remote access commonly concentrates trust in a single authenticated tunnel or portal, then permits broader internal movement than the use case really requires. If that session is stolen, abused or poorly segmented, an attacker can pivot from remote support into plant-facing systems, engineering tools or admin workflows.
Impact: The result can be production disruption, unsafe configuration changes, loss of visibility into operational systems or a wider incident that crosses IT and OT boundaries. In manufacturing, the business impact is often amplified because availability and process integrity matter as much as data confidentiality.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP API Security Top 10 addresses the attack and risk surface, while NIST SP 800-53 Rev 5, NIST Zero Trust (SP 800-207) and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-9 — Identification and Authentication (Non-Organizational Users) | Remote vendor and partner access to plant systems depends on strong non-org authentication. |
| AC-6 — Least Privilege | Zero trust narrows remote sessions to the minimum actions needed on plant assets. | |
| Recommendation — Require strong authentication for external remote access into manufacturing environments. Limit each remote session to the minimum permissions needed for the support task. | ||
| NIST Zero Trust (SP 800-207) | 3.1 — Variability in Trust | The question is about replacing broad inherited trust with contextual access decisions. |
| Recommendation — Replace network-based trust with continuous, context-aware access decisions. | ||
| CIS Controls v8 | CIS-6 — Access Control Management | Manufacturing remote access needs tighter control over who can reach which operational assets. |
| Recommendation — Tighten and review remote access permissions for production-connected systems. | ||
| OWASP API Security Top 10 | API8 — Security Misconfiguration | Legacy remote access often fails through overly broad or misconfigured access paths. |
| Recommendation — Harden remote-access configurations so sessions cannot overreach into plant systems. | ||
Practitioner Guidance
What to prioritise: Treat zero trust as the default when remote access can reach systems that affect production, safety or uptime. If the remote path only supports occasional low-risk administration, a legacy model may still be tolerable, but once it touches plant operations, assume the blast radius matters more than convenience.
What to verify: Confirm whether remote support paths are still granting broad network reach, whether devices are checked before access is granted, and whether sessions are limited to the minimum asset and action required. If any of those three are missing, the environment is already past the point where trust-by-network is a safe assumption.
What good looks like: The right end state is not “no remote access,” but remote access that is scoped, logged, revocable and tied to identity plus device context. Zero Trust Identity Guide is a useful reference point for aligning that model with continuous verification and phased adoption.
Practitioner takeaway: Manufacturing teams should move to zero trust when remote access becomes operationally normal and capable of influencing production, because at that point the main problem is no longer connectivity, it is controlling the scope and consequence of every session.