Most people associate phishing with fake login pages and stolen passwords.
But modern attackers don’t always need your credentials.
Sometimes, all they need is one click on a legitimate OAuth consent screen:
✅ “Allow access”
That single approval can grant a malicious app access to:
- your email
- your cloud files
- your contacts
- persistent access via refresh tokens (depending on scope)
Why this attack works
OAuth is built for convenience and secure delegation.
The problem is: users often approve scopes without reading them.
High-risk scopes to watch for
If you're working in security or IAM, these are worth extra attention:
- Mail.Read / Mail.ReadWrite
- Files.Read / Files.ReadWrite
- offline_access
- Contacts.Read
- User.Read (combined with others)
Defensive checklist (quick)
✅ Restrict user consent where possible
✅ Require admin approval for high-risk scopes
✅ Monitor new app consents + risky scope grants
✅ Revoke sessions + tokens during incident response
✅ Train users: “Allow access” is also an attack surface
I wrote a full beginner-to-pro breakdown here:
🔗 https://danielisaace.medium.com/oauth-consent-phishing-when-allow-access-becomes-a-breach-26f241aa4523
If you’ve seen OAuth abuse in real environments, what detection signal worked best for you?
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