The owning team, the platform team, and the governance function all share accountability because deprecated access is a lifecycle failure, not a single technical mistake. The practical standard is simple: if an API can still authenticate, someone still owns its risk, even if the original use case has ended.
Why This Matters for Security Teams
An abandoned API rarely stays harmless just because the original project ended. If it can still authenticate, it can still be abused for lateral movement, data access, or privilege escalation, which makes ownership a risk decision rather than a paperwork exercise. NHI Management Group’s Ultimate Guide to NHIs — Key Challenges and Risks highlights how often service accounts and API keys outlive their intended purpose, while the OWASP Non-Human Identity Top 10 frames stale credentials and weak lifecycle control as recurring control failures, not isolated incidents.
The practical problem is that legacy access is often inherited across teams: application owners assume the platform owns it, platform teams assume the service is retired, and governance assumes someone else has confirmed revocation. That gap is where abandoned identities become active attack paths. In practice, many security teams encounter this only after a secrets leak, an incident review, or a failed decommissioning audit has already exposed the missing ownership.
How It Works in Practice
Risk ownership for an abandoned API should follow the identity lifecycle, not the org chart. The owning application or product team is usually accountable for business justification, the platform or infrastructure team is accountable for technical enforcement, and the governance or risk function is accountable for ensuring the control exists and is reviewed. That shared model aligns with NIST Cybersecurity Framework 2.0, which treats identity, access, and asset lifecycle management as operational responsibilities that must be continuously maintained.
In practice, the control objective is simple: no API should remain authenticated without a current owner, a documented purpose, and a revocation trigger. Mature programmes usually combine these steps:
- Tag the API, service account, and secrets with an owner, system, and expiry date.
- Require decommissioning approval before an API can be retired or left dormant.
- Rotate or revoke secrets when the use case changes, not only when an incident occurs.
- Alert on authentication from inactive or unreferenced endpoints.
- Review third-party and CI/CD dependencies that may still call the API after internal retirement.
NHI Management Group research shows why this matters: only 20% of organisations have formal processes for offboarding and revoking API keys, and 91.6% of secrets remain valid five days after notification of compromise in the Ultimate Guide to NHIs. That is not just an operations issue. It means the risk persists well after the team believes the asset is gone. These controls tend to break down in heavily automated CI/CD environments because ephemeral deployments, copied secrets, and undocumented integrations make it difficult to prove that no remaining workload still depends on the abandoned API.
Common Variations and Edge Cases
Tighter revocation controls often increase operational friction, so organisations have to balance security certainty against the cost of breaking a still-needed dependency. That tradeoff is especially real when APIs support partner integrations, long-lived batch jobs, or shadow IT consumers that were never formally onboarded.
Current guidance suggests treating these cases as exceptions with explicit expiry, monitoring, and re-approval rather than allowing indefinite access. If an API is technically abandoned but still serves downstream systems, the owner must either reassign responsibility, formally extend the lifecycle, or remove the dependency. There is no universal standard for this yet, but best practice is to require a named business owner plus a technical custodian before access survives any retirement decision.
For risk committees, the key distinction is that an “abandoned” API is only abandoned in intent, not in exposure, until authentication is actually removed. That is why governance should measure revoked access, not just closed tickets, and why platform teams should verify that secrets, tokens, and certificates are no longer valid. In environments with federated ownership or outsourced operations, the risk often remains ambiguous until a clear revocation workflow exists across both internal and external parties.
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-03 | Stale API access reflects poor NHI lifecycle and rotation control. |
| NIST CSF 2.0 | PR.AC-4 | Abandoned APIs expose access control gaps that CSF expects to be governed. |
| NIST AI RMF | Shared accountability fits AI risk governance for persistent digital access. |
Assign accountable owners, review residual access, and document revocation decisions.
