Treat third-party access as a managed identity relationship with an owner, scope, expiry, and revocation process. Review not only what the supplier account can do directly, but also what it can reach through connected applications and delegated trust. That approach reduces hidden blast radius and makes supplier access auditable.
Why This Matters for Security Teams
Third-party access is where identity programs often lose control of the actual blast radius. A supplier account may look narrow on paper, yet still inherit trust through API scopes, delegated admin, OAuth grants, and connected applications. That is why governance has to extend beyond the account itself and into the apps, tokens, and approvals that sit behind it. NHI research shows the scale of this problem: 92% of organisations expose NHIs to third parties, and only 5.7% have full visibility into service accounts, according to Ultimate Guide to NHIs.
Security teams should treat every third-party identity as a governed relationship with a defined purpose, owner, expiry, and offboarding path. That approach is consistent with the direction in NIST Cybersecurity Framework 2.0 and the access-centric risks highlighted in OWASP Non-Human Identity Top 10. In practice, many security teams encounter excessive supplier reach only after a contract ends, an integration changes, or an OAuth grant is abused.
How It Works in Practice
Effective third-party governance starts with inventory, but it cannot stop at inventory. Each supplier identity should be linked to a business owner, a technical owner, an approved use case, the systems it may touch, and a revocation trigger. Current guidance suggests pairing RBAC with explicit scope controls so the supplier can only do what the contract and workflow permit. Where possible, use JIT access and short-lived secrets so the supplier does not keep standing access longer than necessary.
For high-risk integrations, the better pattern is intent-based authorisation: approve the action at runtime, not just the identity at enrolment. That matters when a third party can chain tool access through delegated trust or OAuth consent. The operational goal is to make every grant observable, time-bound, and reviewable, not merely authenticated. Top 10 NHI Issues and 52 NHI Breaches Analysis both underscore how weak lifecycle control and hidden privileges turn third-party identities into long-lived attack paths.
- Assign a named owner for every supplier identity and every delegated trust relationship.
- Limit entitlements to the smallest app, API, and environment scope that supports the business task.
- Set expiry by default, then require explicit re-approval for renewal.
- Log the identity, the action, the target system, and the delegated path used.
- Revoke both the direct account and any connected grants during offboarding.
These controls tend to break down in federated environments with multiple app owners and unmanaged OAuth consent, because no single team can see the full trust chain.
Common Variations and Edge Cases
Tighter third-party control often increases operational friction, requiring organisations to balance supplier speed against auditability and revocation certainty. That tradeoff is real, especially for managed service providers, development partners, and SaaS integrations that need ongoing access. Best practice is evolving, but there is no universal standard for how much delegated trust should be allowed without human approval.
One common exception is emergency access during incident response. In those cases, JIT elevation may be acceptable, but only with strong logging, a short expiry, and a post-use review. Another edge case is machine-to-machine access in CI/CD or data pipelines, where the third party is not a person at all but a workload. Those relationships still need the same governance discipline: identity ownership, secret rotation, scoped permissions, and clean offboarding. NHI programs often miss this distinction until exposed connections create a breach path, which is why Cisco DevHub NHI breach and Reviewdog GitHub Action supply chain attack are useful reminders.
For organisations adopting stronger Zero Trust models, third-party access should be treated as continuously verified rather than permanently trusted. That aligns with NIST Cybersecurity Framework 2.0 and the practical guidance in OWASP Non-Human Identity Top 10. The hardest cases are legacy suppliers, shared service accounts, and consent grants that were never designed for expiry, because they resist clean ownership and revocation.
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 AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-05 | Third-party grants often become hidden standing access paths. |
| NIST CSF 2.0 | PR.AC-4 | Least-privilege access and approval flow fit supplier governance. |
| NIST AI RMF | If third parties include AI agents, runtime accountability is essential. |
Inventory supplier identities, scope their permissions, and revoke unused grants on a fixed cadence.
Related resources from NHI Mgmt Group
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on May 28, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
