Use IGA for human lifecycle controls and add NHIM for service accounts, API keys, tokens, and certificates. Machine identities are often created dynamically by applications, so they need continuous inventory, ownership, rotation, and decommissioning controls that do not depend on HR events or periodic human access reviews.
Why Machine Identities Need a Different Governance Model
Teams usually reach for IGA because it is the established control plane for joiners, movers, leavers, approvals, and periodic access reviews. That works well for people, where employment events create a natural lifecycle. Machine identities behave differently: they are created by pipelines, platforms, and applications, then consumed by other systems, so governance has to follow the technical lifecycle rather than the HR lifecycle.
The practical implication is that machine identity governance must answer four questions continuously: what exists, who owns it, where it is used, and when it should expire. A good IAM and IGA Basics model helps teams separate human entitlement governance from machine credential governance, and the Human vs Non-Human Identity guide is useful when teams need to draw that boundary cleanly.
Machine identities also change faster than many teams expect. Service accounts, API keys, tokens, and certificates may be created for a deployment, rotated by automation, or embedded in a service that has no direct human owner. If governance waits for a quarterly review cycle, the inventory is already stale. That is why ownership, discovery, and expiry tracking are part of governance, not just operational hygiene.
What Control Model Fits Service Accounts, API Keys, Tokens, and Certificates?
The control model should treat machine identities as managed assets with explicit lifecycle states, not as exceptional technical artifacts. In practice, this means continuous discovery, assignment of a responsible owner, policy-based rotation, and a defined decommissioning path when a workload, integration, or environment is retired. NHI Lifecycle Management Guide is a strong fit for this pattern because it centers the lifecycle work that IGA was not designed to perform for machines.
For authentication design, teams should prefer a model that limits secret sprawl and avoids long-lived static credentials where possible. NHI Authentication Guide is relevant because it shows the range of machine-to-machine authentication patterns that need governance, while the SPIFFE workload identity specification illustrates how workload identity can be made more explicit and automatable than ad hoc secret distribution.
Ownership is the control that keeps the model from collapsing. Every machine credential should have a named service owner, a system of record for where it is issued, and a retirement trigger tied to the workload, application, or integration that consumes it. Without that, teams end up with orphaned credentials that no one is accountable for rotating or removing.
How Should Teams Operate Governance Day to Day?
Day-to-day governance works best when human and machine processes are deliberately split. Use IGA for human approvals, certifications, segregation of duties, and HR-driven lifecycle events. Use machine-focused controls for inventory, credential rotation, environment separation, usage monitoring, and decommissioning. The strongest operating model is one where the human governance workflow can see machine identities, but does not pretend that human review cadence is sufficient to control them.
This is also where continuous evidence matters. Teams should be able to show current inventory, last-rotated date, owner, scope, environment, and retirement status for each machine identity. The Access Reviews and Certification Guide is helpful when teams need to adapt certification practices so that reviews produce action, not just sign-off, and the Joiner-Mover-Leaver (JML) Guide is useful as the human-side contrast for understanding why machine identity lifecycle cannot depend on employee status changes.
When the estate is large, the key measurement is not how many credentials exist, but how many are owned, scoped, rotated, and actually removed when no longer needed. That is the signal that governance is working. Teams that only measure review completion often miss the harder problem, which is whether the review process changed any machine access at all.
Risk and Threat Considerations
Machine identities become a security problem when they outlive the workload, retain excess scope, or are shared across systems without clear ownership. That creates a quiet but durable attack path because stolen keys, tokens, and certificates can be reused outside the normal human lifecycle and may not trigger the same review mechanics that govern people. The risk is highest when credentials are long-lived, broadly privileged, or difficult to inventory.
Failure mechanism: The organization treats machine credentials as exceptions, so they are created outside normal governance, never fully inventoried, and are not revoked when applications change, are retired, or are cloned into new environments.
Impact: Attackers or insiders who obtain one of these credentials can persist, move laterally, or access production services long after the original business need has passed. Operationally, the same weakness also drives orphaned access, failed audits, and rotation outages when no owner can safely update the credential.
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 addresses the attack surface, NIST SP 800-53 Rev 5 and CIS Controls v8 set the technical controls, and ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Machine credentials need rotation, revocation, and expiry controls. |
| IA-9 — Service Identification and Authentication | Service accounts and workloads authenticate to each other, not just humans. | |
| AC-6 — Least Privilege | Machine identities often accumulate excess access beyond their task scope. | |
| Recommendation — Manage machine authenticators with rotation, revocation, and expiry rules. Apply service authentication controls to workload and API trust paths. Restrict each machine identity to the minimum required privileges. | ||
| ISO/IEC 27001:2022 | A.5.16 — Identity management | Machine identities still need managed identity assignment and ownership. |
| A.5.17 — Authentication information | API keys, tokens, and certificates require controlled handling and rotation. | |
| A.8.5 — Secure authentication | Machine-to-machine authentication needs secure credential handling and assurance. | |
| Recommendation — Define a process to register, assign, and govern machine identities. Protect and rotate authentication information used by machine identities. Use secure authentication methods for service and workload access. | ||
| CIS Controls v8 | CIS-5 — Account Management | Machine accounts require inventory, ownership, and removal when no longer needed. |
| Recommendation — Inventory machine accounts and remove stale or unowned entries promptly. | ||
| OWASP Non-Human Identity Top 10 | NHI-01 — Improper Offboarding | Machine identities must be decommissioned when workloads or integrations end. |
| NHI-07 — Long-Lived Secrets | Static machine secrets are a core governance and exposure problem here. | |
| Recommendation — Tie deprovisioning to workload retirement and remove unused machine identities. Replace long-lived machine secrets with shorter-lived, rotated credentials. | ||
Practitioner Guidance
What to prioritize: Put ownership and inventory ahead of policy wording. If you cannot prove which workload uses a credential and who can retire it, the governance model is not ready for scale.
Decision rule: If a credential can authenticate to production, treat it as a controlled asset with explicit expiry, rotation, and removal criteria. If it is embedded in a deployment pipeline or application config, require the retirement path before approving the deployment.
What to verify: Verify that human access review processes do not substitute for machine lifecycle controls. The practical test is whether the team can rotate or decommission a credential without waiting for a human employment event.
Practitioner takeaway: IGA should govern people, but machine identities need their own lifecycle discipline, because the control failure is usually not missing approval, it is missing ownership, visibility, and retirement.