Cross-site request forgery (CSRF) vulnerability in doorkeeper before 1.4.1 allows remote attackers to hijack the authentication of unspecified victims for requests that read a user OAuth authorization code via unknown vectors.
Doorkeeper versions prior to 1.4.1 are vulnerable to a Cross-Site Request Forgery (CSRF) attack, allowing attackers to potentially hijack user authentication and gain unauthorized access to OAuth authorization codes. This vulnerability could lead to sensitive data exposure and account compromise. Exploitation requires a victim to be logged into a Doorkeeper-protected application and tricked into visiting a malicious website or clicking a crafted link.
Step 1: Victim Login: The victim is logged into an application that uses Doorkeeper for OAuth authentication.
Step 2: Malicious Payload Delivery: The attacker crafts a malicious HTML page or email containing a hidden form or JavaScript code.
Step 3: Victim Interaction: The victim unknowingly interacts with the malicious content. This could be by visiting a compromised website, clicking a malicious link, or opening a crafted email.
Step 4: Forged Request: The malicious code triggers a forged request to the Doorkeeper application. This request attempts to retrieve the victim's OAuth authorization code.
Step 5: Code Retrieval: Due to the lack of CSRF protection, the Doorkeeper application processes the forged request and, if successful, retrieves the victim's authorization code.
Step 6: Attacker Access: The attacker receives the victim's authorization code, which can then be used to impersonate the victim and access protected resources.
The root cause lies in the lack of proper CSRF protection within the Doorkeeper gem. Specifically, the authorization code retrieval process is susceptible to manipulation. The application fails to validate the origin of requests, allowing an attacker to craft a malicious request that, when executed by a logged-in user, retrieves their authorization code without their consent. This flaw stems from the absence of CSRF tokens or other mechanisms to verify the request's authenticity, enabling attackers to forge requests and trick the server into providing sensitive information.