Because certificates, servers, and devices also authenticate to corporate systems and influence what can reach sensitive resources. If they are excluded from identity governance, organisations leave a parallel access estate outside review and control. Treat them as identity-bound credentials with ownership, review, and revocation requirements.
Why machine certificates belong in the same governance model as user accounts
Machine certificates are not just technical plumbing. They are credentials that prove a device, server, service, or workload is allowed to connect, sign, or request access, so they shape who can reach sensitive systems and how much trust the environment extends. Once a certificate is used as an authentication factor, its ownership, expiry, rotation, and revocation become governance issues, not only infrastructure tasks.
That is why organisations should treat certificates as part of identity governance rather than as isolated infrastructure artefacts. A certificate with no named owner, no review cycle, or no revocation path can outlive the system that issued it and continue to grant access after the original need has changed.
What changes when certificates are governed like identities
Governance changes the question from “is the certificate technically valid?” to “is this certificate still authorised for this business purpose?” That distinction matters because a valid certificate can still be risky if it belongs to a retired service, a shared integration, or a workload that now has broader access than intended. Governance should therefore cover issuance, business ownership, approved use, renewal, and retirement.
This also brings certificates into the same lifecycle logic as user access. Just as user accounts need joiner-mover-leaver handling, machine certificates need inventory, assignment to an owner, periodic attestation, and a clear revocation trigger when the underlying system, role, or trust relationship changes.
- Assign each certificate to a named service owner, system owner, or platform owner.
- Track where it is used, what it authenticates to, and what trust boundary it crosses.
- Review expiry, renewal method, and revocation coverage before the certificate becomes business-critical.
Why unmanaged machine certificates create the same class of access risk as unmanaged accounts
When machine certificates are excluded from governance, they become a parallel access estate that attackers and operators can both rely on. A certificate can unlock API calls, mutual TLS sessions, code-signing trust, or backend access without appearing in the same review queues as human accounts. That makes it easy to miss, over-entitle, or leave active long after the original purpose has ended.
The practical failure mode is stale trust. If a certificate is still accepted by downstream systems after the associated workload, device, or integration should no longer exist, it can preserve access even when other controls have changed. Governance closes that gap by tying the credential to ownership, policy, and revocation rather than to the issuing mechanism alone.
For certificate lifecycle management, Machine Identity, PKI and Certificate Lifecycle Guide is the most direct internal reference for expiry, automation, and revocation discipline.
Risk and Threat Considerations
Machine certificates can fail in ways that mirror account compromise: overlong validity, poor inventory, weak ownership, and delayed revocation all widen the window for misuse. The risk is not limited to outage. A still-trusted certificate can also be abused for lateral access, unauthorized service-to-service calls, or persistence after a system change.
Failure mechanism: The environment trusts a certificate because it is cryptographically valid, even though the business relationship behind it has ended or changed. That creates a control gap between technical validity and authorised use.
Impact: Attackers or insiders can keep using the credential to reach internal services, while defenders lose the ability to prove which certificates should still be trusted and which should have been revoked.
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 and risk surface, while NIST SP 800-53 Rev 5 and NIST SP 800-57 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 — Improper Offboarding | Certificates can outlive the system or trust relationship they support. |
| NHI-02 — Secret Leakage | Certificates are identity-bearing material that must be protected and inventoried. | |
| NHI-05 — Overprivileged NHI | Machine certificates often grant access beyond what the workload needs. | |
| Recommendation — Revoke machine certificates when their owner, workload, or business purpose ends. Protect certificate material and prevent exposure in repos, logs, and images. Limit certificate-backed access to the minimum trust scope required. | ||
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Certificate lifecycle, rotation, and revocation are authenticator management concerns. |
| IA-9 — Service Identification and Authentication | Machine certificates authenticate services and workloads to each other. | |
| AC-6 — Least Privilege | Certificates should only authorize the access a machine actually needs. | |
| Recommendation — Enforce expiration, rotation, and revocation for certificate authenticators. Use service authentication controls for machine-to-machine certificate trust. Constrain certificate-backed access to the minimum required privileges. | ||
| NIST SP 800-57 | Key lifecycle management | Certificate governance depends on sound key and certificate lifecycle handling. |
| Recommendation — Manage certificate-related keys with defined generation, protection, rotation, and destruction rules. | ||
Practitioner Guidance
What to prioritise: Start with discovery and ownership. If you cannot tie a certificate to a service, application, device, or team, you cannot govern it with the same confidence you apply to a user account.
What to verify: Confirm that renewal, expiry, and revocation are operationally tested, not just documented. A certificate programme is weak if it depends on manual memory at rotation time or if expired credentials can linger in production trust stores.
What good looks like: Every certificate has an owner, a purpose, a review cadence, and a revocation path, with short-lived credentials or automated renewal where the platform supports it. Governance should make it easy to answer who owns it, why it exists, and when it should stop working.
Practitioner takeaway: The key judgement is to treat certificates as governed access material, because cryptographic trust without lifecycle control is still standing access.
Related resources from NHI Mgmt Group
- When do service accounts become a higher risk than ordinary user accounts?
- Why do service accounts and privileged user accounts need the same governance discipline?
- Why do system accounts and machine tokens need tighter governance than ordinary user accounts?
- Why do non-human identities create more audit risk than human accounts?