How should organisations evaluate third-party app permissions before granting access to cloud drives?

What organisations should test before approving cloud-drive app access

Start by treating the permission request as a description of what the app can read, change, or exfiltrate, not as a generic “connect your account” prompt. The practical question is whether the app needs narrow file-level access, folder-level access, or full-drive visibility, and whether the requested scope matches the business task the integration is supposed to perform.

A useful review also asks who stands behind the app and how its trust model works. A third-party integration may be legitimate but still too broad for the task, especially when it can access content beyond the immediate user workflow, retain tokens, or move data into another environment where your controls are weaker.

How to judge permission scope, trust, and data reach

Look at scope in three layers: the specific data the app can reach, the actions it can perform, and the persistence of that access. If a vendor only needs to index a single shared folder, broad drive-wide read permissions are a mismatch. If the app can also write, sync, or create links, the risk changes because it can alter records, not just observe them.

That assessment should be tied to least privilege and to the app’s actual operating model. The same principle appears in OWASP Non-Human Identity Top 10, which highlights overprivilege and third-party risk in connected integrations, and in SaaS-to-SaaS and OAuth App Governance Guide, which focuses on consent scopes, token risk, and revocation discipline for connected apps.

Evaluate whether the app can be constrained to a narrower audience, a narrower set of files, or a shorter-lived grant. If the vendor cannot explain why broad access is required, or cannot show how access is segmented between customers, treat that as a warning sign rather than an implementation detail.

What good review and revocation practice looks like

The strongest approval process does not end at initial consent. It includes a periodic recheck of business need, a review of active scopes, and a clean removal path for apps that are no longer used. That matters because cloud-drive permissions often outlive the project that justified them.

Reviewers should also confirm whether the integration is operating through a manageable OAuth pattern or through some other standing grant that is harder to constrain. Where the app depends on broad delegated access, the organisation should understand the blast radius of a compromised token and the speed with which access can be revoked.

For teams building a standard approval workflow, the most useful reference points are the broader access-governance model in IAM and IGA Basics and the control perspective in Cloud PAM and CIEM Guide, which both reinforce rightsizing, effective permissions, and review of what is actually used.

Risk and Threat Considerations

Third-party drive apps become a high-value target when they are granted broad read or write access, because a single compromised token can expose a large body of content without further user interaction. The risk is not limited to malicious apps, because a well-intentioned integration can still over-collect, retain data too long, or expose information through a weak vendor environment.

Failure mechanism: Excessive scope, long-lived grants, or weak vendor controls let an attacker or careless integration turn one approved app into a path across many files, folders, or users.

Impact: The result can be data theft, silent copying of sensitive files, unauthorized modification, or lateral movement into other SaaS systems that trust the same token or consent chain.

Practitioner Guidance

What to verify: Confirm the exact permission set, the minimum data set the app truly needs, and whether the vendor can technically enforce that limit. If the app cannot explain its access boundary in plain terms, do not approve it on trust alone.

What to prioritise: Focus first on apps with broad read permissions, write permissions, offline access, or access to shared drives and high-value document repositories. Those conditions create the largest blast radius if the token or vendor account is compromised.

Decision rule: If the requested scope is wider than the stated business use, reject or narrow it before approval; if the scope is appropriate, set a review date and require a removal path when the use case ends.

Practitioner takeaway: The question is not whether the app is useful, but whether its access can be constrained to the smallest defensible boundary and revoked quickly when that boundary is no longer needed.

Related resources from NHI Mgmt Group

• Should organisations re-evaluate agent access after a third-party app is connected to core systems?
• How should organisations evaluate third-party cybersecurity before sharing sensitive data or access?
• What breaks when organisations do not review third-party app permissions?
• Why does NIST CSF 2.0 matter for organisations trying to govern access risks across cloud, application, and third-party environments?