How should manufacturers replace shared credentials in production environments without disrupting operations?

Manufacturers should move from shared usernames and passwords to person-level authentication at shared terminals, HMIs, and workstations. The goal is to make every login attributable to one individual while preserving operational flow. Biometric sign-in, scoped access, and unified identity governance help reduce ambiguity, limit credential reuse, and create accountability across both IT and OT environments.

Why This Matters for Security Teams

shared credentials are efficient on the surface, but in production they erase accountability, make password rotation risky, and turn every terminal into a potential lateral-movement point. That is especially dangerous in manufacturing, where shared HMIs, kiosks, and operator stations must stay online while shifts change and equipment cannot pause for manual resets. Current guidance from the OWASP Non-Human Identity Top 10 and NIST identity controls favors traceable, least-privilege access over communal logins.

The operational risk is not only unauthorized access. Shared accounts complicate incident response, undermine segregation of duties, and make it harder to tell whether an action came from an operator, a contractor, or a compromised workstation. NHIMG’s Ultimate Guide to NHIs — Static vs Dynamic Secrets frames the core issue well: static credentials persist long after the need for access has changed, while production environments need controlled, attributable access that can adapt by shift, role, and system state. In practice, many security teams discover shared-account abuse only after an outage, audit finding, or malware event has already exposed the weakness.

How It Works in Practice

The practical replacement for shared credentials is not simply “more passwords.” It is person-level authentication paired with scoped authorization at the point of use. In a plant, that usually means each operator signs in with their own identity at a shared terminal, HMI, or workstation, then receives access only to the functions needed for that task. The identity layer should integrate with policy enforcement, not bypass it, so the system can distinguish between viewing telemetry, acknowledging alarms, approving changes, and performing privileged maintenance.

Manufacturers typically combine several controls:

• Single sign-on tied to a durable human identity for attribution and auditability.
• Role-based or context-aware access that narrows what a user can do after sign-in.
• Fast re-authentication for sensitive actions, such as recipe changes or safety overrides.
• Session timeouts and automatic lock policies that fit shift handoffs.
• Break-glass workflows for emergency access with mandatory logging and post-event review.

For high-friction floors, biometric sign-in or badge-plus-PIN can reduce time lost during shift changes, but best practice is evolving: the right factor mix depends on safety, hygiene, and device constraints. Where the workload is more machine-to-machine than person-to-machine, the same principle extends to workload identity and short-lived secrets. NHIMG’s Guide to the Secret Sprawl Challenge and the NIST SP 800-53 Rev 5 Security and Privacy Controls both support tighter credential handling, while NIST SP 800-63 Digital Identity Guidelines provides the identity assurance foundation for replacing communal access with attributable sign-ins.

These controls tend to break down in legacy OT cells where one application account is hard-coded into vendor software and the line cannot tolerate downtime for a redesign.

Common Variations and Edge Cases

Tighter authentication often increases friction at first, so manufacturers have to balance operator speed against auditability and safety. The edge case is not whether shared credentials are bad in principle, but whether every production endpoint can support individual authentication without creating work stoppages. In some environments, the answer is to phase the change: start with shared terminals, then move privileged actions, then retire the communal account entirely.

There is no universal standard for this yet in brownfield OT, especially where vendor support is limited or equipment runs on embedded systems that cannot join modern identity stacks. In those cases, compensating controls matter: unique account vaulting, session brokering, command allowlists, and monitored jump hosts can reduce exposure until the plant can modernize. NHIMG’s research on the 2024 Non-Human Identity Security Report shows that many organisations already see value in dynamic ephemeral credentials, which is relevant when production systems need short-lived, attributable access rather than shared static passwords.

For teams planning the transition, the useful test is simple: if an operator leaves the floor, can the organisation still prove exactly who did what, and can access be revoked without affecting the line? If not, the environment still depends on shared trust instead of controlled identity.

Related resources from NHI Mgmt Group

• How should manufacturers eliminate shared logins in OT without disrupting operations?
• How should organisations govern identity in OT environments without disrupting operations?
• How should security teams implement microsegmentation in industrial environments without disrupting production?
• How should financial institutions run penetration testing in complex, always-on environments without disrupting operations?