Why do third-party vendors create such high compliance and security risk for organisations?

Why This Matters for Security Teams

Third-party risk is a governance problem as much as a technical one. A supplier may be the organisation’s weakest link, but the accountability usually remains with the buyer, especially when customer data, regulated workflows, or critical services are involved. Current guidance from the NIST Cybersecurity Framework 2.0 makes that shared-responsibility reality explicit: identify external dependencies, assess the impact of failure, and monitor controls continuously rather than at onboarding alone.

Security teams often underestimate how quickly vendor access expands beyond the original use case. A finance processor, SaaS administrator, managed service provider, or analytics platform can become embedded in core operations, which creates exposure across identity, data handling, resilience, and legal obligations. The issue is not only whether the vendor is secure; it is whether the organisation can evidence due diligence, contractual control, and ongoing oversight when auditors or regulators ask. In practice, many security teams encounter vendor risk only after access sprawl, data exposure, or service interruption has already made the issue visible.

How It Works in Practice

Managing third-party risk effectively means treating vendors as part of the control environment, not as external exceptions. That starts with classifying the service by data sensitivity, system criticality, privilege level, and business dependency. A low-risk marketing tool does not need the same scrutiny as a payroll processor or cloud operations partner, but both need a documented rationale for approval and review. Mature programmes align this to control families in NIST SP 800-53 Rev 5 Security and Privacy Controls and to the supplier lifecycle in ISO/IEC 27001:2022 Information Security Management.

Practically, teams should assess four layers:

• Security posture: policies, testing, incident response, and independent assurance.
• Identity and access: how vendor users, service accounts, API keys, and credentials are issued, rotated, and revoked.
• Data governance: what data is accessed, processed, stored, or transferred, and where it resides.
• Operational resilience: backup, recovery, change management, and outage handling.

This is where NHI governance increasingly matters. Vendors often depend on non-human identities such as API keys, certificates, automation tokens, and service principals. If those secrets are long-lived or poorly inventoried, the organisation can lose control of who or what is acting on its behalf. The OWASP Non-Human Identity Top 10 is relevant here because third-party integrations frequently create standing access that survives contract changes, employee turnover, or tool decommissioning. These controls tend to break down in fast-moving SaaS ecosystems where procurement, IT, and security each assume another team owns revocation.

Common Variations and Edge Cases

Tighter vendor control often increases onboarding time and administrative overhead, requiring organisations to balance assurance against business speed. That tradeoff is real, especially when the supplier is strategic, the market is concentrated, or the service is needed urgently. Best practice is evolving toward risk-based segmentation rather than universal checklists, because one-size-fits-all reviews create either false confidence or control fatigue.

Edge cases matter. A supplier may be low risk contractually but high risk operationally if it holds privileged support access or can trigger automated workflows. A cloud platform may have strong certifications yet still create exposure through tenant configuration, shared responsibility gaps, or weak customer-side identity controls. Regulators and auditors also care about evidence, not intent, so due diligence must be repeatable: review records, exception handling, breach notification clauses, and offboarding proof. Where financial crime or customer onboarding is involved, the same vendor due diligence can overlap with FATF Recommendations expectations for KYC and AML controls. The hardest failures usually appear when a “temporary” integration becomes permanent, but the permissions never do.

Related resources from NHI Mgmt Group

• Why do third-party services create such a large data security risk?
• Why do third-party data sprawl and shared links create such high breach risk?
• Why do third-party vendors create so much identity risk?
• Why do third-party vendors create identity and access risk?