OAuth2: Predictable State II

This exercise covers the exploitation of predictable state in the OAuth2 Client

PRO
Tier
Hard
1-2 Hrs.
232

Course


The course delves into the exploitation of an insecure OAuth2 Client that relies on a predictable state parameter, often based on the current time, making it susceptible to attacks. By registering a malicious account on the Authorization Server and going through the OAuth2 dance, one can inspect the state parameter. Combined with a CSRF attack, this vulnerability can be used to link the victim's account to the attacker’s account, thereby gaining unauthorized access.

The exploitation involves creating an HTML page to prime the victim's session and redirect them with the correct state parameter. A dynamic web page is recommended for fetching the current state and generating the malicious payload. This exercise underscores the importance of securing OAuth2 implementations to prevent such critical vulnerabilities.

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