Why do third-party relationships create identity and access risk?

Why Third-Party Access Becomes an Identity Problem

Third-party relationships are risky because they extend trust outside the core organisation while still touching the same systems, data, and workflows. Once a supplier, contractor, or integration partner receives credentials, API access, or delegated authority, that access becomes part of the identity surface. If lifecycle controls are weak, the relationship outlives the business need and the access path remains open.

The problem is not just who the third party is, but what identity they use and how that identity is governed. NHI Management Group has documented that 92% of organisations expose NHIs to third parties, raising supply chain security concerns in practice; the broader research base also shows how often identity drift, over-privilege, and missed offboarding turn ordinary vendor access into a persistent exposure. Current guidance suggests treating third-party identity as a first-class control domain, not a procurement afterthought, as reflected in the OWASP Non-Human Identity Top 10 and NIST’s NIST Cybersecurity Framework 2.0.

In practice, many security teams encounter vendor-related compromise only after an integration token, service account, or shared admin path has already been abused.

How Third-Party Identity Risk Manifests in Practice

Third-party relationships usually create risk through a small set of repeatable failure modes. The most common is standing access: a vendor account is created once, then left active long after the project, ticket, or support window ends. A second failure mode is excessive privilege, where the external identity inherits broad roles because it is easier than designing narrowly scoped permissions. A third is weak provenance, where the organisation cannot clearly tell whether an action came from a named individual, a service account, a CI/CD integration, or another downstream system.

Effective governance starts by separating the business relationship from the technical entitlement. Procurement may approve the vendor, but security must define the identity, scope, duration, and revocation logic. In current best practice, that means unique identities, per-purpose access, explicit ownership, and frequent access recertification. The Ultimate Guide to NHIs notes that 97% of NHIs carry excessive privileges and 71% are not rotated within recommended time frames, which is exactly why third-party access can become durable attack infrastructure.

• Issue separate identities for vendors, contractors, and managed service providers.
• Limit access to named systems, named tasks, and short time windows.
• Use approval and revocation workflows that are tied to contract status, not informal reminders.
• Log and review every privileged action from an external identity.
• Prefer ephemeral credentials and scoped tokens over shared passwords or long-lived keys.

Where possible, map vendor access to zero standing privilege principles and review the relationship through a lifecycle lens, not just an access-control lens. These controls tend to break down in large SaaS and MSP-heavy environments because identities proliferate faster than ownership, inventory, and revocation processes can keep up.

Common Variations, Edge Cases, and Control Gaps

Tighter third-party access often increases operational friction, requiring organisations to balance response speed against revocation discipline. That tradeoff is most visible in support relationships, emergency access, and machine-to-machine integrations, where a vendor may need immediate entry but only for a very specific task.

There is no universal standard for this yet, but current guidance suggests handling edge cases with explicit compensating controls. For example, emergency vendor access should be time-boxed, monitored in real time, and automatically removed after the incident closes. Managed service providers may need broader reach than a normal contractor, but they should still operate under distinct identities and segmented privileges rather than shared admin credentials. If a third party uses automation, the identity risk often shifts from a human login to a workload identity problem, which makes the Top 10 NHI Issues especially relevant.

For organisations with complex supplier ecosystems, the hardest gap is not authorisation design but ownership. When no one is accountable for revalidating access at contract renewal, identities remain active by default. That is why vendor offboarding must be treated as an identity event, not just a commercial one. In the real world, the control failure usually appears as a forgotten account, a stale token, or a trusted integration that survives long after the relationship changed.

Related resources from NHI Mgmt Group

• Why do third-party vendors create identity and access risk?
• Why do third-party relationships create ongoing identity risk?
• Why do shadow IT apps create identity risk even when users still have valid SSO access?
• Why do third-party identities create a different insider-risk problem?