Securing NHIs for ISO 27001 compliance: the control gap

At a glance

What this is: The article argues that ISO 27001 compliance depends on securing non-human identities because machine credentials often carry broad access and weak lifecycle controls.

Why it matters: This matters because IAM teams cannot satisfy governance, audit, or incident response requirements if service accounts, API keys, and other NHIs sit outside the control model.

By the numbers:

• 72% of organisations have experienced or suspect they have experienced a breach of non-human identities - 46% confirmed, 26% suspected.

👉 Read Entro Security's analysis of NHIs and ISO 27001 compliance

Context

ISO 27001 treats information security as a governance system, not a checklist, and that makes non-human identities part of the control surface. When service accounts, API keys, automation tools, and certificates hold access to systems and data, the question is not whether they exist, but whether they are governed with the same discipline as human identities.

That gap matters because machine identities are frequently over-privileged, long-lived, and poorly observed. In practice, that means access control, cryptographic controls, supplier oversight, and incident response all depend on NHI hygiene, which is why IAM and security teams need a single view of identity across people, workloads, and automation.

Key questions

Q: How should security teams govern non-human identities for ISO 27001 compliance?

A: Treat NHIs as governed identities, not technical leftovers. Assign ownership, scope each identity to a defined task, protect credentials in a vault, and review whether access still matches the business purpose. ISO 27001 compliance depends on evidence that machine access is controlled, monitored, and removed when it is no longer needed.

Q: Why do service accounts and API keys create ISO 27001 audit risk?

A: They create audit risk when their permissions are broader than the workflow they support or when no one can explain why the identity still exists. Auditors look for ownership, access scope, rotation, and deprovisioning evidence. Without those controls, machine identities become unmanaged exceptions inside the ISMS.

Q: What breaks when non-human identities are not monitored and reviewed?

A: Detection, accountability, and incident response all weaken at the same time. If an NHI behaves abnormally and the organisation cannot tell whether the activity is expected, the control environment loses credibility. The result is delayed containment, harder forensics, and a higher chance that orphaned access remains active.

Q: How do organisations reduce risk from third-party machine identities?

A: They should treat supplier-connected credentials as part of the same identity governance model as internal NHIs. That means limiting access to the minimum required, rotating secrets, reviewing logs, and confirming that the vendor relationship still justifies the access. Supplier access is only low risk when it is actively governed.

Technical breakdown

Why ISO 27001 access control breaks down for NHIs

ISO 27001 access control assumes permissions can be intentionally limited, reviewed, and removed when no longer needed. NHIs complicate that model because they are embedded in applications, pipelines, and service integrations, often with permissions that outlive the business task they support. A service account may be created for one workflow and then reused across many systems, which makes least privilege difficult to define at provisioning time. The control failure is not just excess access. It is the loss of clear ownership over what the identity is allowed to do, when, and by whom it is being operated.

Practical implication: Map every non-human identity to a business owner, task scope, and expiry condition before granting access.

How cryptographic controls should be applied to machine credentials

Cryptographic controls in an NHI context are about protecting credentials, tokens, keys, and certificates wherever they exist in the operational chain. ISO 27001 expects sensitive material to be protected in transit and at rest, but that is only part of the problem. Machine identities often leak through code, configuration files, CI/CD variables, or shared vault access paths. If the secret is not isolated from the workflow that uses it, encryption alone does not stop overuse or reuse. The technical goal is to reduce secret exposure while preserving machine-to-machine authentication.

Practical implication: Store machine secrets in managed vaults and remove embedded credentials from code and configuration.

Why logging and supplier relationships are the same NHI problem

Operational security and supplier management converge when third-party systems authenticate with your environment through API keys, service accounts, or tokens. ISO 27001 requires visibility into activity and risk across external relationships, but machine identities can obscure which supplier did what, and whether access still matches the contract. Logging becomes the evidence layer for both control and accountability, while supplier governance determines whether the identity should exist at all. If the audit trail cannot distinguish expected machine activity from abnormal use, detection and compliance both weaken.

Practical implication: Correlate NHI activity logs with vendor ownership, contract scope, and review cadence to support audit and response.

Threat narrative

Attacker objective: The attacker aims to turn a trusted machine identity into quiet, repeatable access across systems and data.

1. Entry occurs through an exposed or over-shared machine credential, such as an API key, service account password, or certificate that was never fully scoped to a single task.
2. Escalation follows when the compromised identity has broader permissions than the workflow needs, allowing the attacker to move from one system to another or access sensitive data.
3. Impact appears as data exposure, service disruption, or a wider breach because the machine identity was trusted as a normal operational actor.

Breaches seen in the wild

• IOS app secrets leakage report — iOS apps leaking hardcoded secrets and credentials endangering user privacy.
• Cisco DevHub NHI breach — IntelBroker exploited exposed Cisco credentials, API tokens and keys in DevHub.

Read our 52 NHI Breaches Analysis report for a comprehensive view of breaches impacting Non-Human Identities including AI Agents.

NHI Mgmt Group analysis

ISO 27001 does not stop at human access, and neither should identity governance. The standard's access, cryptographic, supplier, and incident controls all assume that every credentialed actor is accounted for. When NHIs are treated as operational leftovers instead of governed identities, the ISMS loses coverage exactly where automation concentrates risk. Practitioners should read ISO 27001 as an NHI governance test, not just a policy exercise.

Non-human identity governance gap: this is the point where compliance language meets operational reality. Service accounts, API keys, and certificates are often created for delivery speed, then left outside the review cycle that governs human access. That creates a gap between declared control and actual control, and auditors will eventually ask who owns the identity, what it can reach, and when it expires. The implication is that NHI governance must be embedded into the ISMS, not appended to it.

Least privilege is harder to prove for NHIs because machine access is frequently distributed across workflows. A single identity may support application calls, vendor integrations, and background jobs, which makes the effective privilege footprint larger than the provisioning record. That is a structural governance issue, not a tuning problem. Practitioners need to rethink how entitlement scope is described when the actor is a machine rather than a person.

Monitoring alone is not sufficient if the identity lifecycle is unmanaged. ISO 27001's operational and incident controls depend on the ability to identify, log, review, and disable identities when their purpose ends. If inactive or orphaned NHIs remain in place, response becomes retrospective instead of preventative. The practical conclusion is simple: lifecycle discipline determines whether monitoring produces evidence or just noise.

Supplier access is an identity problem, not only a contract problem. Third-party systems often authenticate through the same NHI patterns that internal teams use, which means vendor risk management and machine identity governance are inseparable. If external access is not scoped, rotated, and reviewed with the same rigor as internal service accounts, the organisation inherits the supplier's identity risk as its own. Security teams should treat vendor-connected NHIs as part of the core control set.

From our research:

• 72% of organisations have experienced or suspect they have experienced a breach of non-human identities, 46% confirmed and 26% suspected, according to the 2024 ESG Report: Managing Non-Human Identities.
• Enterprises that have experienced a compromised NHI averaged 2.7 separate incidents in the past 12 months, according to the same report.
• For a broader control baseline, review Ultimate Guide to NHIs. Lifecycle Processes for Managing NHIs for provisioning, rotation, and offboarding discipline.

What this signals

NHI governance is becoming an ISO control issue, not a niche infrastructure concern. As automation expands, the organisations that separate human IAM from machine IAM will keep finding gaps in their ISMS evidence. The practical signal is that identity teams should expect NHI ownership, review, and expiry to appear more often in audit conversations, especially where supplier access and secrets management intersect.

With 85% of organisations lacking full visibility into third-party vendors connected via OAuth apps, per the State of Non-Human Identity Security, supplier-linked identities are now a governance blind spot. That blind spot will matter more as ISO 27001 programmes are asked to prove not just internal control, but control over delegated machine access. Teams should prepare for deeper evidence requests around vendor-owned credentials and access scope.

Identity lifecycle discipline will become the differentiator. The programmes that can show inventory, ownership, rotation, and deprovisioning for NHIs will move faster through compliance work and recover faster from incidents. The ones that cannot will keep treating audit as an after-the-fact cleanup exercise.

For practitioners

• Inventory every non-human identity Build a complete register of service accounts, API keys, tokens, certificates, and automation identities, including ownership, purpose, and expiry conditions.
• Bind each NHI to least privilege and a named owner Require a business owner, task scope, and access ceiling for every machine identity before it is approved for use.
• Move secrets into managed vaults Remove credentials from code, configuration files, and shared pipelines, then enforce retrieval through a controlled vault path.
• Audit inactive and orphaned identities regularly Review machine identities on a recurring schedule, disable unused accounts, and verify that supplier-connected access still matches contract scope.

Key takeaways

• ISO 27001 compliance depends on governing non-human identities with the same discipline used for human access.
• Machine credentials create audit, incident response, and supplier-risk exposure when ownership, scope, and lifecycle controls are missing.
• Teams should inventory, rotate, vault, and regularly review NHIs before they become the weakest evidence point in the ISMS.

Key terms

• Non-Human Identity: A non-human identity is a credentialed digital actor used by systems, applications, services, or automation to authenticate and access resources. In practice, this includes service accounts, API keys, tokens, certificates, and similar secrets that must be governed with ownership, scope, rotation, and offboarding controls.
• Machine Identity Lifecycle: Machine identity lifecycle is the set of processes used to create, approve, use, rotate, review, and retire non-human identities. For NHIs, lifecycle discipline is the control that prevents stale credentials, orphaned access, and unclear ownership from becoming persistent security debt.
• Least Privilege for NHIs: Least privilege for NHIs means giving a machine identity only the permissions required for its specific task and no more. Because machine access often supports applications and integrations rather than people, the effective privilege footprint can expand quickly unless scope, ownership, and expiry are explicitly managed.
• Secrets Vault: A secrets vault is a controlled storage system for credentials such as keys, tokens, passwords, and certificates. For NHIs, the vault is not just storage, it is part of the access path, because it limits exposure, supports controlled retrieval, and helps keep secrets out of code and configuration.

What's in the full article

Entro Security's full blog covers the operational detail this post intentionally leaves for the source:

• How Entro maps ISO 27001 control areas to specific NHI practices such as access control, logging, and supplier management.
• The article's step-by-step framing for securing service accounts, API keys, tokens, and certificates in line with the standard.
• Additional implementation context for vaulting, rotation, and audit evidence that practitioners can use when building an ISMS.
• The source's own walkthrough of why NHI governance supports incident handling and post-incident review.

👉 Entro Security's full post covers the control mapping, NHI examples, and compliance framing in more detail.

Deepen your knowledge

NHI governance, lifecycle control, and secrets handling are core topics in our NHI Foundation Level course, the industry's only accredited NHI security programme. If you are aligning machine identity controls to ISO 27001, it is worth exploring.