New Phishing Attacks Exploiting OAuth Authorization Flows (Part 1)

This blog series expands upon a presentation given at DEF CON 29 on August 7, 2021.

Phishing attacks are starting to evolve from the old-school faking of login pages that harvest passwords to attacks that abuse widely-used identity systems such as Microsoft Azure Active Directory or Google Identity, both of which utilize the OAuth authorization protocol for granting permissions to third-party applications using your Microsoft or Google identity.

In the past few years, we have seen illicit grant attacks that use malicious OAuth applications created by attackers to trick a victim into granting the attacker wider permissions to the victim’s data o…