Who is accountable for non-human identity risk when a service account or API key is over-permissioned?

Why This Matters for Security Teams

Over-permissioned service accounts and API keys create an ownership problem before they create a technical one. The immediate risk is not only unauthorized access, but also the absence of a clear decision-maker when access must be reduced, rotated, or revoked. NHI Management Group’s Ultimate Guide to NHIs notes that 97% of NHIs carry excessive privileges, which means this is a widespread governance failure, not an edge case. Security teams can detect drift, but detection alone does not answer who is responsible for the business impact.

Practitioners should treat accountability as an asset-level control, not a ticketing function. A named business or technical owner is the only party able to explain why the identity exists, what systems it can touch, and which exceptions are justified. That distinction matters because identity sprawl often hides in build systems, integrations, and unattended automation. The OWASP Non-Human Identity Top 10 frames this as a lifecycle and privilege problem, not merely an access review issue. In practice, many security teams discover the over-permissioned key only after a breach review, rather than through intentional ownership and review.

How It Works in Practice

Effective accountability starts with mapping each service account or API key to a named owner, a documented purpose, and a specific workload or integration. That owner should be able to approve access, justify exceptions, and confirm remediation when permissions exceed need. Security and IAM teams define the policy, but they do not own the business rationale. The control objective is simple: no identity should exist without a person or team that can answer why it exists and what breaks if it is removed.

In operational terms, this means tying non-human identities to inventory, ticketing, and change records, then enforcing review at creation, change, and offboarding. The NIST Cybersecurity Framework 2.0 and NIST SP 800-53 Rev 5 Security and Privacy Controls both support this model through asset governance, access restriction, and continuous monitoring. For NHI-specific exposure, NHI Management Group’s 52 NHI Breaches Analysis is a useful reminder that compromised credentials are often operationally valid long after they should have been retired.

• Assign every service account and API key to one accountable owner, not a shared mailbox or generic team queue.
• Require the owner to document business purpose, data access scope, and upstream and downstream dependencies.
• Set review triggers for privilege expansion, environment changes, and inactivity.
• Make exception approval time-bound and revocable, with a defined remediation date.
• Escalate identities with no owner to the default disposition: restrict, quarantine, or retire pending review.

These controls tend to break down in CI/CD pipelines, third-party integrations, and legacy batch jobs because ownership is inherited informally and permissions accumulate faster than anyone updates the record.

Common Variations and Edge Cases

Tighter ownership often increases operational overhead, requiring organisations to balance clear accountability against delivery speed. The tradeoff is real: if every API key change requires manual sign-off, teams may bypass process; if no one is named, over-permissioned access lingers indefinitely. Current guidance suggests the best answer is tiered ownership, with low-risk identities handled through lightweight approvals and high-risk identities subject to formal review.

There is also no universal standard for how to handle shared service accounts, ephemeral automation, or vendor-managed identities. In those cases, the owner may be a platform team, product team, or contract sponsor, but the identity still needs a single accountable party. Where service accounts support multiple applications, the owner should document the dominant use case and retire any permissions that are only justified by historical convenience. The Top 10 NHI Issues and Guide to the Secret Sprawl Challenge both show how quickly unmanaged credentials spread once ownership becomes ambiguous. For AI-adjacent workflows, the same principle applies to keys exposed in model tooling and agent pipelines, where the accountable party must understand both the workload and the blast radius.

Related resources from NHI Mgmt Group

• Why do non-human identities create more audit risk than human accounts?
• Why do non-human identities create audit risk in modern environments?
• Why do non-human identities create compliance risk even when policies exist?
• When does a short-lived API key still create material risk?