How do organisations reduce the risk of malicious app-to-app connections in business SaaS platforms?

Organisations should restrict app approvals, require security review for sensitive scopes, and continuously monitor non-human identities such as API keys, OAuth tokens, and service accounts. They should also remove unnecessary connections quickly and verify that every integration has a clear business owner. This reduces the chance that a seemingly harmless app becomes a durable entry point.

Why This Matters for Security Teams

App-to-app connections in SaaS often bypass the controls security teams apply to human users. Once an OAuth grant, API key, or service account is approved, it can persist quietly and operate far beyond the original business need. That makes malicious integrations especially dangerous: they can read data, move laterally across SaaS tenants, and retain access long after the business owner has forgotten the app exists.

Current guidance suggests treating these connections as non-human identities rather than “just integrations.” The risk is not only unauthorized data access, but also hidden privilege accumulation through delegated scopes, stale tokens, and overbroad app permissions. The Ultimate Guide to NHIs notes that 97% of NHIs carry excessive privileges, which is exactly why SaaS-to-SaaS trust relationships need review and continuous monitoring. NIST also frames this as access control and ongoing authorization, not one-time setup, in the NIST Cybersecurity Framework 2.0.

In practice, many security teams encounter malicious app connections only after data exfiltration, token abuse, or a third-party breach has already turned a normal integration into a durable entry point.

How It Works in Practice

The practical control set starts with tighter app approval and scope governance. Security and platform teams should classify SaaS integrations by risk, then require review for apps that request mail, file, directory, admin, or cross-tenant scopes. For lower-risk apps, approval can be streamlined, but the business owner still needs to be explicit and accountable.

At the identity layer, the app should be managed as an NHI with a known owner, purpose, scope, and expiry. That means tracking OAuth grants, API keys, refresh tokens, and service accounts as inventory objects, not as incidental configuration. The control objective is to keep privileges narrow, time-bound, and revocable. The most effective programs tie this to change management and periodic recertification, so dormant connections are removed before they become shadow access paths.

Monitoring is equally important. Security teams should log consent events, token creation, scope expansion, unusual API calls, and access from abnormal tenants or locations. The Top 10 NHI Issues highlights how often organisations lose visibility into non-human identities, and the Salesloft OAuth token breach shows why a compromised app connection can become a high-value path into downstream SaaS data. NIST SP 800-53 Rev 5 reinforces this approach through access enforcement, audit logging, and least privilege controls.

• Require business justification for every integration.
• Review sensitive scopes before approval and again at renewal.
• Prefer short-lived credentials and rapid revocation paths.
• Alert on dormant, overprivileged, or newly expanded app grants.

These controls tend to break down in federated SaaS estates where departments can approve apps independently because no single team owns the full consent and revocation lifecycle.

Common Variations and Edge Cases

Tighter app controls often increase friction for business teams, so organisations have to balance agility against containment. That tradeoff is most visible in marketing, sales, and automation-heavy environments where legitimate workflow apps are added quickly and removed slowly. Best practice is evolving, but the direction is clear: delegate routine approvals only for low-risk integrations, while keeping high-risk or cross-domain scopes under central review.

There is no universal standard for this yet, but some organisations are moving toward intent-based approvals, where the request must specify the exact data objects, duration, and downstream systems involved. That helps separate a one-time automation from a standing integration. For inherited SaaS tenants, the edge case is legacy connections created before governance existed; those often need a bulk review and forced re-consent cycle rather than a normal quarterly attestation.

Another common gap is third-party app trust. Even if the app is legitimate, a vendor compromise can turn a normal consent into a breach path. The BeyondTrust API key breach is a reminder that SaaS risk includes upstream compromise, not just malicious insiders. Organisations that already follow the 2024 ESG Report: Managing Non-Human Identities from Oasis Security & ESG know the problem is widespread, with two-thirds of enterprises reporting a successful cyberattack resulting from compromised NHIs.

These controls tend to fail when app permissions are treated as procurement decisions instead of security decisions, because ownership and revocation never become operational disciplines.

Related resources from NHI Mgmt Group

• How should security teams reduce risk from malicious SaaS app approvals and fake updates?
• How should organisations decide whether to integrate AI agents with other security platforms through protocol-based connections?
• How do organisations reduce exposure when high-risk activity appears in real time?
• When should organisations treat an NHI as a high-priority risk?