Why do shared devices create more access risk in manufacturing?

Why This Matters for Security Teams

Shared devices in manufacturing are not just a convenience issue. They create a security problem because access is often optimized for throughput, not identity certainty. When multiple operators, maintenance staff, contractors, and shift leads reuse the same terminal, it becomes harder to prove who did what, whether a session should still be trusted, and whether a privileged action was appropriate at that moment. That is exactly where OWASP Non-Human Identity Top 10 style thinking becomes useful: identity risk is about more than a login prompt.

Manufacturing environments also tend to mix human access with machine-to-machine workflows, service accounts, and local tool sessions, which means weak device controls can expose far more than a single user account. NHIMG research shows how fast this risk compounds in practice: in Ultimate Guide to NHIs, 97% of NHIs are reported to carry excessive privileges, widening the blast radius when a shared endpoint is abused or left in an inconsistent state. In practice, many security teams encounter shared-device abuse only after production disruption, rather than through intentional identity monitoring.

How It Works in Practice

The main issue is that shared devices blur the boundary between the device, the session, and the person. If a terminal stays logged in, caches credentials, or uses a generic workstation account, the next operator may inherit access that was never meant for them. If reauthentication is slow, teams often bypass controls to keep the line moving. That creates a pattern where convenience overrides assurance.

Effective controls usually combine device-level hardening with strong session design. A practical approach is to require fast user switching, short-lived sessions, and step-up authentication before sensitive actions such as recipe changes, quality overrides, or maintenance mode. Where possible, organisations should pair this with NIST Cybersecurity Framework 2.0 practices for asset management, access control, and monitoring, then map device use to individual accountability rather than workstation ownership alone.

• Use unique operator identities, even on shared endpoints.
• Separate general viewing access from actions that change production state.
• Force session timeout and reauthentication on shift changes or inactivity.
• Limit local cached secrets and remove standing admin access from floor devices.
• Log user, device, timestamp, and action context for every critical change.

For teams managing broader NHI exposure, Ultimate Guide to NHIs also highlights how weak lifecycle controls and excessive privilege drive most identity risk. Shared devices magnify that problem because a single sloppy session can expose both human and non-human access paths at once. These controls tend to break down in high-speed production cells where login friction is treated as downtime and operators are pressured to share accounts.

Common Variations and Edge Cases

Tighter access control on shared devices often increases operational friction, so organisations must balance security assurance against line speed, shift handoffs, and support burden. That tradeoff is real, especially in plants with older equipment, offline terminals, or legacy HMI systems that were never designed for modern identity controls.

Best practice is evolving for environments where shared devices cannot be fully replaced. In those cases, current guidance suggests isolating the most sensitive actions behind additional approval or time-bound access, rather than trying to make every interaction equally strict. For example, a read-only dashboard may tolerate a lower-friction login path, while a device that can alter batch settings should require stronger checks and more detailed audit trails.

Another edge case is contractor-heavy operations. Temporary staff often need quick access across multiple stations, which makes static role design brittle. Shared-device programs work better when access is driven by context, shift, and task, not by a broad local account that stays valid all day. For identity-heavy manufacturing estates, the lesson is simple: the more people and systems that touch the same device, the more important it becomes to know exactly who had access, when, and for what purpose.

Related resources from NHI Mgmt Group

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• Why do shared clinical devices create more access risk than personal devices?