Shared credentials weaken accountability and make it harder to detect misuse, especially in shift-based or contractor-heavy environments. When one login is used by many people, incident response cannot determine who accessed what, and offboarding cannot reliably remove all exposure. That turns a convenience measure into a persistent governance gap.
Why Shared Logins Become a Floor-Level Security Problem
Shared credentials are not just an IT convenience issue. On the factory floor, they collapse accountability across shifts, contractors, and temporary staff, which makes it difficult to prove who accessed a system, changed a setting, or bypassed a control. That breaks basic incident response and weakens preventive controls that depend on identity clarity. Guidance in OWASP Non-Human Identity Top 10 and the NIST Cybersecurity Framework 2.0 both point to the same operational truth: access must be attributable to be governed.
NHIMG research shows how often organisations still rely on weak access handling. In The 2024 Non-Human Identity Security Report, 23.7% of organisations said they share secrets through insecure methods such as email or messaging applications, which is a close cousin of the same control failure. In practice, many security teams encounter misuse only after a quality incident, safety event, or unexplained downtime has already occurred, rather than through intentional access monitoring.
How Shared Credentials Break Traceability and Response
In industrial environments, a shared login usually hides three separate risks: who used it, what they could reach, and whether the access still exists after a worker leaves. Once that identity is reused across people or roles, audit logs stop being useful for forensics because the event trail points to a credential, not a person. That also complicates segregation of duties, because a single account can drift across maintenance, operations, and vendor support tasks without clear approval.
Current guidance suggests replacing shared access with named identities wherever possible, then using role-based access control, privileged access management, and short-lived access for exceptions. For systems that cannot yet support individual human identities, organisations often pair local accounts with stronger compensating controls such as badge-based approval, time-bound elevation, and session recording. NIST identity guidance helps here, but it does not solve the floor-specific problem by itself: the operational need is to know exactly who was authorised at the moment a change occurred.
That is why Guide to the Secret Sprawl Challenge matters alongside standards such as NIST SP 800-63 Digital Identity Guidelines. Shared credentials tend to be copied into handheld terminals, maintenance laptops, and vendor workflows, then forgotten when the equipment changes hands. These controls tend to break down when a production line depends on legacy controllers that cannot support individual authentication because teams keep the shared account as a permanent workaround.
Where Shared Access Sometimes Persists, and What to Do Instead
Tighter identity controls often increase operational overhead, requiring organisations to balance traceability against uptime, contractor friction, and legacy system constraints. That tradeoff is real on the factory floor, where devices may not support modern auth flows and shifts move too quickly for manual approvals. Best practice is evolving, and there is no universal standard for every plant architecture yet.
In those cases, a practical path is to phase out shared credentials by asset class. Start with high-consequence systems such as safety, PLC management, recipe changes, and remote maintenance portals. Then introduce named access, JIT elevation, and stronger authentication for privileged actions. If a shared account cannot be eliminated immediately, reduce blast radius by scoping it to a single machine or cell, rotating secrets frequently, and logging every session to a central system.
- Use individual identities for human operators and contractors wherever the platform supports it.
- Reserve shared accounts only for legacy equipment with a documented retirement plan.
- Pair privileged access with time limits, approvals, and session recording.
- Review access after each shift change, vendor handoff, or incident.
NHIMG’s reporting on credential exposure reinforces the urgency of moving away from reuse. The same control weakness that enables secret sprawl in IT can create physical production risk when an unknown user can still operate a machine after the original owner has left. Shared access tends to persist longest in plants with mixed vendor support, older OT stacks, and weak offboarding discipline because those conditions make identity cleanup operationally expensive.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST CSF 2.0 and NIST SP 800-63 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 | Shared credentials obscure identity attribution and increase secret reuse risk. |
| NIST CSF 2.0 | PR.AC-1 | Access control must distinguish users to preserve accountability and response. |
| NIST SP 800-63 | AAL2 | Stronger digital identity assurance reduces reliance on shared, unverifiable access. |
Use higher-assurance authentication for privileged floor systems and remove shared accounts where possible.
