Start by inventorying every place an agent inherits a human token, shared service account, or embedded API key. Those are the points where attribution, expiry, and scope usually fail first. Once identified, move the highest-risk workflows to unique workload identities and short-lived credentials before expanding the pattern more widely.
What IAM Teams Should Tackle First
The first move is to find every place an AI agent is borrowing someone else’s access, especially human tokens, shared service accounts, and embedded API keys. That inventory tells you where attribution is already weak, where expiry is unclear, and where scope is likely wider than the workflow really needs. From there, the practical shift is to replace the riskiest paths with distinct workload identities and short-lived credentials.
A useful way to frame the problem is that agent authentication is usually not failing at the login screen, it is failing at the delegation boundary. If the same credential can be reused across people, tools, or runs, IAM cannot reliably tell who acted, when access should expire, or what the agent was actually allowed to do.
Where the First Control Breaks Usually Appear
Start by mapping the places where an agent obtains authority rather than assuming the agent has its own identity. The highest-risk patterns are inherited user sessions, shared automation accounts, static keys copied into prompts or config files, and broad tokens that outlive the task they were meant to support. Top 10 NHI Issues is useful here because it highlights discovery, ownership, shared accounts, and credential hygiene as recurring failure modes.
That inventory should separate actual agent credentials from the downstream systems the agent touches. A workflow that only needs to read one API and write to one queue does not need a general-purpose credential that can reach multiple environments. The more a credential behaves like a person’s standing access, the faster attribution and least-privilege controls degrade.
For teams building the inventory, the most important question is not “does the agent work?” but “what identity is the agent using at the moment it works?” If the answer is a reused human token or a long-lived shared secret, the control boundary is already too soft. Ultimate Guide to NHIs is a strong reference point for the identity types involved, including service accounts, API keys, OAuth tokens, certificates, and workload identities.
How to Move From Shared Access to Governed Agent Authentication
Once the risky uses are visible, move the highest-impact workflows first. Replace inherited human credentials with unique workload identities, bind those identities to a single agent or service boundary, and issue short-lived credentials that can be revoked without waiting for a manual cleanup cycle. AI Agent Authorisation Guide supports that pattern by centring task-scoped access, per-action decisioning, and human approval where the action is sensitive.
This is also where teams should distinguish authentication from approval. An agent may authenticate successfully and still be over-authorised for the action it is trying to perform. The right design keeps identity issuance narrow, makes tokens time-bound, and ensures the agent cannot silently reuse the same access path across unrelated workflows.
When a workflow cannot be redesigned immediately, treat the credential as a temporary exception with a defined expiry, owner, and rollback path. That is the practical bridge from inherited access to governed access, and it prevents “temporary” shared credentials from becoming permanent infrastructure.
Risk and Threat Considerations
Inherited human credentials and shared secrets create fast failure paths because they collapse attribution and widen blast radius at the same time. If an agent can act through a human token or a reused key, a compromise or misuse event can look like normal user activity until the damage is already done.
Failure mechanism: The access path is detached from the agent’s actual task boundary, so expiry, ownership, and scope are enforced weakly or not at all. That makes token reuse, secret leakage, privilege creep, and cross-environment movement much easier to miss.
Impact: Teams lose reliable auditability and can overestimate how constrained the agent really is. In practice, that can turn a narrow automation step into a durable standing-access problem.
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 sets the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 — Improper Offboarding | Inherited or shared agent access often fails when credentials are not retired cleanly. |
| NHI-02 — Secret Leakage | Human tokens, API keys, and embedded secrets are the first exposure points in agent authentication. | |
| NHI-05 — Overprivileged NHI | Agents that inherit broad human or shared access are usually over-scoped for the task. | |
| Recommendation — Revoke agent and shared credentials promptly when workflows change or are decommissioned. Store and rotate agent secrets out of code, prompts, and configs. Assign the agent only the minimum permissions needed for each workflow. | ||
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Short-lived credentials, rotation, and revocation are central to governed agent authentication. |
| IA-9 — Service Identification and Authentication | AI agents authenticate as services or workloads when they should not inherit human identity. | |
| AC-6 — Least Privilege | The answer focuses on reducing scope before broadening agent access. | |
| Recommendation — Enforce lifecycle controls for agent credentials, including rotation and expiration. Use distinct service or workload authentication for agents instead of shared user credentials. Limit each agent to the narrowest set of actions and resources required. | ||
Practitioner Guidance
What to prioritise: Inventory first, redesign second. Focus on the workflows where a single credential can unlock multiple systems, because those are the cases most likely to produce attribution gaps and overbroad access.
What to verify: For each agent, verify the issuing identity, the credential lifetime, the exact scopes, and whether revocation actually severs access immediately. If any of those are unclear, treat the workflow as not yet governed.
Decision rule: If the agent is using a human token or shared secret in production, move it to a dedicated workload identity before expanding the pattern anywhere else. If the workflow cannot support that yet, constrain the exception tightly and time-box it.
Practitioner takeaway: The first governance win is not better authentication ceremony, it is eliminating borrowed authority so every agent action can be uniquely owned, time-bounded, and revoked on demand.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on October 7, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org