How should critical infrastructure teams manage privileged access across human operators and non-human identities?

Teams should treat privileged access as a continuous discovery and monitoring problem, not a one-time review. That means identifying engineers, contractors, service accounts, APIs, and field devices, then mapping where elevated access exists, whether it is still needed, and whether it can reach sensitive operational systems. Continuous visibility helps reduce orphaned access and supports compliance.

Why This Matters for Security Teams

Critical infrastructure teams cannot manage privileged access as two separate worlds, one for people and one for machines. Engineers, contractors, service accounts, APIs, field devices, and AI-driven workflows often share the same operational blast radius, and the failure mode is usually privilege sprawl rather than a single bad login. NHI Management Group has found that only 5.7% of organisations have full visibility into service accounts, which is why the control problem starts with discovery, not review, as described in the Ultimate Guide to NHIs.

That matters because privileged access in operational environments is not just an IT concern. A stale API key, over-permissioned service account, or maintenance credential left active after a contractor exits can reach sensitive systems faster than a human operator ever could. Current guidance from the OWASP Non-Human Identity Top 10 and the NIST Cybersecurity Framework 2.0 both point toward continuous identification, least privilege, and monitoring as the only durable approach. In practice, many security teams encounter unauthorized reach into OT or control-plane assets only after a routine credential audit has already missed the exposure.

How It Works in Practice

The practical model is to treat privileged access as a single policy domain with different identity types, not as separate programs for humans and NHIs. That means first building an inventory of every identity that can elevate access: operators with admin roles, break-glass accounts, scripts, service accounts, CI/CD runners, API tokens, certificates, and embedded device credentials. The inventory should also show what each identity can touch, whether access is interactive or machine-to-machine, and whether the credential is static or issued just in time. The Top 10 NHI Issues is useful here because it frames the common failure modes: orphaned credentials, weak rotation, and excessive privilege.

From there, teams should separate authentication from authorisation. Authentication proves which identity is acting. Authorisation should be evaluated at request time, using context such as system state, location, task, time window, and whether the action is expected. For humans, that often means Privileged Access Management, approval workflows, and step-up controls. For NHIs, it usually means short-lived secrets, workload identity, and ephemeral access that expires when the task is complete. Standards-based identity primitives such as SPIFFE and OIDC-style workload tokens are useful because they prove what the workload is, not just what secret it knows. For risk and control mapping, the NIST Cybersecurity Framework 2.0 and the NIST SP 800-53 Rev 5 Security and Privacy Controls remain strong anchors for access enforcement, logging, and continuous assessment.

• Use one access catalog for both human and non-human identities.
• Prefer just-in-time elevation over standing admin rights.
• Rotate and revoke secrets automatically after use or timeout.
• Log every privileged action with identity, context, and downstream effect.
• Review whether an identity can reach OT, safety, or control-plane systems, not just whether it is authenticated.

These controls tend to break down when legacy OT platforms cannot validate short-lived tokens or when vendor-maintained devices require persistent credentials and offline access.

Common Variations and Edge Cases

Tighter privileged access often increases operational overhead, requiring organisations to balance faster restoration and maintenance work against stronger containment. That tradeoff becomes most visible in critical infrastructure, where outages, safety procedures, and vendor support can depend on rapid access that cannot always wait for full approval chains. Current guidance suggests that break-glass access should be rare, time-bound, and heavily monitored, but there is no universal standard for how much delay is acceptable in emergency operations.

Edge cases usually involve legacy systems, third-party field services, and hybrid human-plus-agent workflows. If an AI assistant can open tickets, trigger scripts, or push configuration changes, it should be governed like any other privileged workload, with explicit task scope and short-lived credentials. This is where the NHIMG research on Key Challenges and Risks and Regulatory and Audit Perspectives becomes especially relevant, because audit teams need evidence that privileged access was not only assigned correctly but also removed promptly.

For teams aligning to broader resilience programs, the CISA cyber threat advisories are useful for emerging threat patterns, while the NIST Cybersecurity Framework 2.0 helps translate these controls into measurable governance. The key exception is when a plant or grid environment cannot support modern identity plumbing, in which case teams should segment aggressively and treat persistent privileged access as an exception with compensating controls, not a normal operating state.

Related resources from NHI Mgmt Group

• How should security teams evaluate privileged access management before deploying it across human, machine, and certificate identities?
• How should security teams run access reviews for non-human identities?
• How should security teams govern non-human identities that have persistent access?
• How should security teams audit privileged access across human and non-human identities?