You lose service-level accountability, coarse-grained permissions become too broad, and downstream APIs cannot distinguish which workload should be trusted for which action. That usually leads to over-permissioned services, inconsistent rate limiting, and weak audit trails across internal systems.
Why This Matters for Security Teams
Service-to-service access is not a human workflow with a person behind each request. When teams gate internal APIs with a human identity, they collapse workload identity, runtime context, and accountability into the wrong subject. The result is predictable: broad shared access, weak attribution, and authorization decisions that cannot reflect what the workload is actually doing. OWASP’s Non-Human Identity Top 10 treats this as a core design failure, not a tuning problem.
NHIMG research shows how common the underlying exposure already is. In the Ultimate Guide to NHIs, only 5.7% of organisations report full visibility into their service accounts, while 97% of NHIs carry excessive privileges. If a service is authorised as if it were a person, the control plane cannot tell whether one build job, one payment microservice, or one data pipeline is performing the action. In practice, many security teams discover this only after an internal API has already been overused, impersonated, or chained into a broader incident.
How It Works in Practice
The practical fix is to stop using human identity as the primary control for machine-to-machine access. Current guidance suggests treating workloads as first-class identities with their own authentication, policy, and audit trail. That usually means issuing workload credentials at runtime, binding them to a specific service, cluster, or workload instance, and limiting them to the smallest viable scope.
Common patterns include short-lived tokens, SPIFFE-style workload identity, and policy evaluation at request time rather than at onboarding time. The Top 10 NHI Issues and the Ultimate Guide to NHIs both point to the same operational reality: long-lived shared secrets make service behaviour impossible to reason about once the environment scales.
- Authenticate the workload, not the developer or operator who deployed it.
- Use JIT or ephemeral credentials so access expires with the task, pod, or session.
- Apply policy based on service identity, destination, method, data class, and environment.
- Log the workload subject, not just the source IP or human owner.
This is also where zero trust becomes meaningful for internal systems. The OWASP Non-Human Identity Top 10 aligns with the idea that every call must be re-authorised in context, rather than inheriting trust from the network boundary. These controls tend to break down in legacy monoliths and flat service meshes because identity is shared across too many functions and the API gateway cannot separate one workload’s intent from another’s.
Common Variations and Edge Cases
Tighter workload identity often increases operational overhead, so organisations must balance stronger attribution against rollout complexity. That tradeoff is real, especially when older systems cannot issue per-service credentials or when a single runtime supports many functions. Best practice is evolving, and there is no universal standard for every architecture yet.
Some teams use a human identity only for deployment approval, then switch to workload identity at runtime. That can be acceptable if the deployment pipeline and the service execution path are separately controlled. The important distinction is that the human is authorising release, while the service is authorising its own API calls. For governance and lifecycle discipline, NHIMG’s Ultimate Guide to NHIs — Standards is a useful reference point for aligning identity controls with broader security programmes.
Edge cases appear in batch jobs, serverless functions, and multi-tenant platforms where a single logical “service” can represent many execution contexts. In those environments, coarse identity leads to poor revocation and misleading audit trails. Human identity can remain part of governance, but it should not be the subject that downstream systems trust for machine actions.
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 and CSA MAESTRO address the attack and risk surface, while NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 | Machine access must use workload identity, not human credentials. |
| CSA MAESTRO | IAM | Agent and service authorization needs context-aware runtime controls. |
| NIST AI RMF | Governance must account for autonomous or software-driven action paths. |
Replace shared human auth with distinct workload identities and scoped machine-to-machine trust.
Related resources from NHI Mgmt Group
- What breaks when Kubernetes access is controlled only by network location?
- How should security teams decide whether JIT access is safe for non-human identities?
- What breaks when teams use the same JIT model for all access?
- How should teams choose a Kubernetes ingress controller for identity-based access?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on June 11, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
