Certificate lifecycle management should be shared across security, OT operations, and infrastructure teams, with clear ownership for issuance, renewal, inventory, and revocation. OT environments are too operationally sensitive for manual tracking, so governance needs defined handoffs and automation.
Why This Matters for Security Teams
Certificate lifecycle ownership in OT is rarely just an identity question. It affects plant uptime, safety systems, patch windows, vendor access, and incident response. When no one owns issuance, renewal, inventory, and revocation end to end, certificates become hidden operational dependencies that fail quietly until they trigger outages or force emergency workarounds. Guidance from the NIST Cybersecurity Framework 2.0 reinforces that governance and asset visibility must be explicit, not implied.
NHIMG research shows how often lifecycle failure is already the problem, not a future risk. The NHI Lifecycle Management Guide and the Ultimate Guide to NHIs — Lifecycle Processes for Managing NHIs both point to the same operational reality: unmanaged lifecycle tasks create avoidable exposure, while ownership gaps make remediation slow and inconsistent. In OT, that risk is amplified because certificate expiry can affect systems that cannot tolerate surprise changes or downtime. In practice, many security teams encounter certificate ownership gaps only after a control system has already stopped trusting a service, rather than through intentional governance.
How It Works in Practice
The most effective model is shared ownership with named accountability. Security should define policy, minimum cryptographic standards, approval criteria, and revocation expectations. OT operations should own system dependency mapping, maintenance windows, and validation that renewal actions do not break field equipment or safety workflows. Infrastructure or platform teams should own the certificate tooling, automation, and integration with PKI, inventory, and monitoring systems.
This division works best when certificate lifecycle management is treated as a formal workflow, not a ticket queue. A practical setup usually includes:
- an authoritative inventory of every certificate, system, and service dependency
- automated discovery and expiry alerting well before renewal windows close
- JIT issuance or short-lived certificates where the environment supports it
- documented revocation authority for compromised or retired assets
- change control that coordinates OT validation before renewal or replacement
Current guidance suggests that manual spreadsheets are not adequate for large OT estates, especially where certificates are tied to embedded devices, legacy HMIs, historians, or vendor-managed systems. The OWASP Non-Human Identity Top 10 is useful here because it frames machine credentials as a lifecycle problem, not just a storage problem. NHIMG’s Top 10 NHI Issues also highlights how ownership ambiguity and poor visibility turn routine maintenance into recurring security debt. These controls tend to break down when OT devices are vendor-locked, offline for long periods, or too fragile to support automated renewal without production impact.
Common Variations and Edge Cases
Tighter certificate control often increases operational overhead, requiring organisations to balance uptime against governance discipline. That tradeoff is especially visible in OT, where legacy protocols, air-gapped segments, and vendor service contracts can make full automation unrealistic. Best practice is evolving, and there is no universal standard for this yet, but the ownership model still needs to be explicit even when the tooling is constrained.
Some environments will centralise most technical execution in infrastructure or a PKI team while leaving OT operations responsible for business validation only. Others will push certificate handling to site teams because maintenance windows are local and highly specialised. Either approach can work if the RACI is clear and security retains authority over minimum policy, exception handling, and revocation. Where teams lose control is in exception sprawl, especially when temporary renewals become permanent and certificate inventories drift away from actual plant reality. For that reason, the strongest programs align certificate lifecycle to the same governance discipline described in the Ultimate Guide to NHIs — Regulatory and Audit Perspectives. In vendor-heavy plants, ownership also becomes blurred if third parties can request, install, or replace certificates without internal approval.
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 CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Covers lifecycle control gaps that drive certificate expiry and unmanaged machine identities. |
| NIST CSF 2.0 | GV.OV-01 | OT certificate ownership is a governance and oversight problem requiring explicit accountability. |
| NIST CSF 2.0 | PR.AA-01 | Certificates are identity artifacts that must be managed as part of asset and identity assurance. |
Define governance for certificates, map responsibilities, and verify lifecycle controls through oversight reviews.
Related resources from NHI Mgmt Group
- How should organizations prioritize environments for NHI management?
- How should agencies automate certificate lifecycle management in hybrid environments?
- How should teams govern certificate lifecycle management in multi-cloud environments?
- What breaks when machine identity management stays tied to manual certificate processes?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on June 25, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
