OAuth Attack Persistence – Hackers Maintain Access After Password Resets

Cybercriminals are using a new method to stay inside corporate systems — even after password resets.
Security researchers have identified an OAuth attack persistence technique that allows hackers to retain long-term access to compromised accounts.
The discovery highlights a major blind spot in enterprise identity security.

Proofpoint analysts revealed that attackers exploit OAuth to register malicious internal apps inside company environments.
These apps receive trusted permissions and can survive standard remediation efforts.
Even when users reset passwords or enable multi-factor authentication (MFA), attackers can continue to access emails and files.

How the OAuth Attack Works

Attackers first gain initial access through phishing or token theft.
They then create or compromise an internal OAuth application within the organization’s Microsoft 365 or Google Workspace directory.
The app receives high-level permissions such as Mail.Read or offline_access, which generate long-lived access tokens.
These tokens remain valid even after password changes.

Because the app exists inside the organization’s environment, most defenders treat it as safe.
This false trust allows attackers to quietly monitor inboxes, calendars, and shared documents for weeks or months.
The OAuth attack persistence model effectively turns legitimate infrastructure into a covert backdoor.

Why It’s So Dangerous

Unlike normal credentials, OAuth tokens rarely expire quickly.
Some can remain valid for years unless manually revoked.
That makes the OAuth attack persistence model ideal for long-term espionage or data theft.

Attackers can silently exfiltrate sensitive documents, forward emails, or reset MFA configurations without triggering alerts.
Traditional response actions like password resets or account disabling will not stop them.

How Organizations Can Defend Themselves

Security experts recommend proactive monitoring and strict application control:

• Audit internal and third-party OAuth apps weekly.
• Revoke and delete unrecognized or suspicious app registrations.
• Enforce short token lifespans and mandatory token revocation.
• Restrict who can register OAuth apps in the organization.
• Educate administrators about OAuth persistence and identity-based threats.

Conclusion

The OAuth attack persistence technique changes how defenders must view account security.
Passwords and MFA are no longer enough to end a breach.
Organizations must monitor every app connection, review token permissions, and enforce immediate revocation.
Only by controlling OAuth access can companies prevent attackers from maintaining hidden footholds inside their networks.