How to Detect OAuth Access from SaaS Applications in Google Workspace
- Martin Snyder
- Jul 23
- 3 min read
If you're in charge of IT or security, you've likely had that moment—the one where you find out a third-party SaaS app has access to your Google Workspace, and no one remembers approving it. It might’ve been installed months ago by someone who’s no longer with the company. Now it has access to Gmail, Drive, Calendar, or worse—and you’re left wondering how many other apps are flying under the radar.
The culprit behind this? OAuth.
OAuth is the protocol that allows apps to connect to Google Workspace without needing a password. It’s convenient for users—but it’s also one of the biggest blind spots for security teams.
Why OAuth Access Creates Risk
OAuth was built to make authentication easier. But it also gives apps long-term access to company data—sometimes with very few restrictions. Once granted, many apps retain those permissions indefinitely.
Here’s why that’s a problem:
Over-permissioned apps can read emails, download files, or act on a user's behalf.
Unmanaged identities (e.g., personal Google accounts) often go completely undetected by IT.
Lack of visibility makes it hard to know which apps are connected, what data they can access, and who approved them.
These apps don’t always show up in traditional endpoint or SIEM logs, and without dedicated tools, many go unnoticed until it’s too late.
How to Detect OAuth Access in Google Workspace
If you're using the Google Admin Console, you can manually review which apps have been granted OAuth access by going to:
Security → API Controls → App Access Control
You’ll be able to view authorized apps, scopes, and user activity. But this approach doesn’t scale well—especially in environments with hundreds or thousands of users.
If you're looking for something faster and more complete, Waldo Security offers a free OAuth Discovery Tool for Google Workspace that provides instant visibility into your connected SaaS ecosystem.
What Waldo’s Free Tool Can Do
With just a few clicks, the tool:
Scans your entire domain for third-party OAuth grants—no need to chase individual users
Lists every connected app, who authorized it, and what level of access it has
Flags risky apps with high-scope permissions or known security concerns
Provides action steps for revoking or restricting access via Google Admin Console
The tool connects securely with read-only access and doesn’t retain any sensitive data. Most teams see meaningful results in under 10 minutes.
Why Visibility Matters
OAuth isn’t just a convenience—it’s also a major attack vector. In 2020, malicious OAuth apps were used to bypass multi-factor authentication and gain persistent access to Microsoft and Google environments. These weren’t sophisticated malware attacks. They were simple app approvals that users didn’t fully understand.
The same thing can happen in your environment—unless you know what’s connected.
How Waldo Security Can Help Long-Term
Waldo’s free tool is a great starting point, but if you need ongoing monitoring, policy enforcement, and automated offboarding of SaaS access (especially for unmanaged identities), Waldo Security offers enterprise-grade solutions built for exactly this use case.
Our platform helps organizations:
Continuously monitor OAuth and SaaS access
Discover unmanaged accounts and shadow IT
Automatically revoke risky permissions across Google Workspace and Microsoft 365
Enforce compliance and reduce exposure
Take Back Control Before It’s Too Late
SaaS adoption has exploded—but so have the risks. OAuth is now one of the easiest ways for data to leak, and most companies don't even know where the gaps are.
You can’t secure what you can’t see. Get visibility into your OAuth landscape before a forgotten app becomes a serious incident.
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