How should manufacturing teams govern machine identities in production environments?

Why This Matters for Security Teams

Machine identities in production are not just authentication artifacts. In manufacturing, they often operate HMIs, connect MES and SCADA layers, trigger maintenance jobs, and call APIs that can affect uptime and safety. That makes governance a reliability issue as much as a security issue. Current guidance suggests treating these identities as managed operational assets, with owners, scope limits, and revocation paths aligned to plant change control, not as static secrets left to drift. The Top 10 NHI Issues research shows 97% of NHIs carry excessive privileges, which is especially dangerous where a single credential can span multiple lines or sites.

That risk is easier to miss in plants because production environments often mix legacy protocols, vendor remote access, and uptime-first operating models. Security teams may know a service account exists, but not which controller, robot cell, or historian depends on it. Frameworks such as NIST Cybersecurity Framework 2.0 help structure this work, but the real requirement is operational traceability from identity to process. In practice, many security teams encounter privilege creep only after a line-stop investigation forces a rushed credential reset.

How It Works in Practice

Effective governance starts with inventory, purpose, and ownership. Every machine identity should be mapped to a business service, a technical owner, and a production impact level. That map should include where the identity authenticates, what it can change, and how quickly it can be revoked without breaking safe operations. The lifecycle guidance in Ultimate Guide to NHIs — Lifecycle Processes for Managing NHIs is useful here because manufacturing teams need onboarding, rotation, review, and offboarding steps that are testable against plant procedures.

From there, apply the least disruptive controls first:

• Use RBAC only where role boundaries are stable, and narrow those roles to one production function.
• Prefer JIT access for maintenance, vendor support, and break-glass actions so standing access is reduced.
• Store secrets in a managed vault, rotate them on a defined schedule, and verify rotation does not interrupt control loops.
• Require approval paths that involve operations leadership when revocation could affect safety, availability, or quality.
• Log every privileged action so incident teams can reconstruct who or what changed a recipe, setpoint, or interface.

This is where NIST Cybersecurity Framework 2.0 and the audit-focused view in Ultimate Guide to NHIs — Regulatory and Audit Perspectives complement each other: one gives the control structure, the other reinforces evidence collection. The goal is not perfect centralisation, but a reversible operating model that can remove access without creating an unsafe recovery path. These controls tend to break down when plants rely on undocumented vendor accounts shared across multiple assets because ownership and revocation become impossible to prove quickly.

Common Variations and Edge Cases

Tighter credential control often increases downtime risk during maintenance windows, so organisations must balance rapid recovery against stronger governance. That tradeoff is especially visible in brownfield plants, third-party support contracts, and multi-site environments with mixed PLC generations. Best practice is evolving, but there is no universal standard for how much autonomy a vendor identity should retain during an incident. The practical answer is to segment by criticality: line controllers, safety systems, historians, and remote service paths should not share the same trust model.

Edge cases also appear when a single identity serves both machine-to-machine traffic and human break-glass access. That pattern should be separated whenever possible, because it obscures accountability and makes revocation unsafe. In higher-risk environments, the incident question is not only whether a secret is valid, but whether the identity can still be trusted after a process fault or unplanned shutdown. The broader non-human identity lifecycle work in Top 10 NHI Issues is especially relevant when production teams discover that a forgotten service account outlived the system it was created for.

Manufacturing teams should therefore treat exemptions as temporary and documented, not as permanent exceptions. When that discipline is missing, the default becomes inherited access, and inherited access is exactly what turns a routine maintenance identity into a plant-wide recovery problem.

Related resources from NHI Mgmt Group

• How should security teams govern machine identities in manufacturing environments?
• How should security teams govern non-human identities in cloud environments?
• How should security teams govern non-human identities at scale?
• How should security teams govern non-human identities for compliance?