How should security teams govern third-party connections that rely on API keys and OAuth tokens in cloud environments?

Why This Matters for Security Teams

API keys and OAuth tokens are not just integration plumbing. In cloud environments they become standing delegated trust, often with access to SaaS data, storage, CI/CD systems, and internal APIs. That makes third-party connections a primary NHI governance problem: once a token is issued, the security posture depends on visibility, scope, rotation, and revocation discipline. NIST’s Cybersecurity Framework 2.0 emphasizes continuous governance, and NHIMG research on the state of non-human identity security shows why that matters: 85% of organisations lack full visibility into third-party vendors connected via OAuth apps.

The common failure is assuming an approved app is inherently low risk. In practice, the risk comes from what the token can reach, how long it remains valid, and whether the vendor or integration is still trusted. A leaked key can bypass normal user authentication, and an over-scoped OAuth grant can quietly persist long after the business owner has forgotten it. Current guidance suggests treating these connections as continuously governed identities, not one-time setup tasks. In practice, many security teams encounter abuse only after a vendor token has already been used to exfiltrate data or chain into other services, rather than through intentional review.

How It Works in Practice

Governance starts with an inventory of every machine-to-machine and third-party connection, including which app owns the credential, which cloud accounts it touches, what scopes or permissions it has, and whether the token is user-delegated or service-issued. That inventory should be tied to data classification so the team can distinguish a low-risk read-only webhook from a token that can export customer records or modify production workloads. The OWASP Non-Human Identity Top 10 is useful here because it frames common control gaps around rotation, over-privilege, and stale credentials.

Security teams should then enforce three operational controls:

• Least privilege by default, with OAuth scopes narrowed to the minimum needed for the integration.
• Credential rotation and expiry, especially for API keys that never naturally time out.
• Fast revocation when the vendor is compromised, the use case ends, or the app behaves outside expected patterns.

Monitoring should look for dormant tokens, impossible travel for service accounts where that concept applies, unusual API call volume, and access to data categories that were never approved. NHIMG’s Guide to the Secret Sprawl Challenge is especially relevant because exposure is often broader than code repositories alone, while incidents such as the Salesloft OAuth token breach show how a third-party token can become a direct path into customer systems. These controls tend to break down when organisations cannot map a token back to a clear owner, business purpose, and revocation path across multiple SaaS tenants.

Common Variations and Edge Cases

Tighter token governance often increases operational overhead, requiring organisations to balance integration speed against auditability and revocation discipline. That tradeoff is most visible with developer tools, marketing SaaS, and managed service providers that want broad, long-lived access. Best practice is evolving, but there is no universal standard for whether every OAuth grant must be re-consented on a fixed schedule; many teams instead use risk-tiered review based on scope, data sensitivity, and inactivity.

Edge cases matter. Some OAuth apps are legitimate but noisy, producing frequent automated calls that can look suspicious unless baselined. Some API keys are embedded in ephemeral workloads, where rotation has to be automated or the service will fail. In other cases, the token is technically valid but the vendor relationship has changed, so the correct action is immediate revocation rather than another review cycle. NHIMG’s reporting on the 52 NHI Breaches Analysis and the Dropbox Sign breach both reinforce the same lesson: visibility without enforcement is not governance. A practical program should combine owner attestation, automated expiry where possible, and immediate disablement paths for high-risk integrations.

Related resources from NHI Mgmt Group

• How should security teams govern third-party app access to cloud accounts in a zero trust model?
• How should security teams govern non-human identities in cloud environments?
• How should security teams govern API keys used for generative AI access?
• How should security teams govern third-party OAuth grants in enterprise environments?