Source: secalert@redhat.com
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, a popular OAuth provider, is vulnerable to a Cross-Site Request Forgery (CSRF) attack. This allows attackers to potentially hijack user authentication and gain unauthorized access to protected resources by tricking victims into making requests to the Doorkeeper server. Successful exploitation could lead to data breaches and account compromise.
Step 1: Victim Logged In: The victim is logged into a Doorkeeper-protected application using their credentials and has an active session with the Doorkeeper server.
Step 2: Attacker Crafting: The attacker crafts a malicious web page or email containing a hidden form or JavaScript code.
Step 3: Payload Delivery: The attacker lures the victim to visit the malicious web page or open the malicious email.
Step 4: Request Trigger: The malicious code automatically submits a request to the Doorkeeper server, targeting the endpoint responsible for handling authorization code retrieval. This request is crafted to appear as if it originates from the victim's browser.
Step 5: Code Retrieval: Because of the missing CSRF protection, the Doorkeeper server processes the request, potentially revealing the victim's OAuth authorization code.
Step 6: Code Exploitation: The attacker uses the stolen authorization code to obtain an access token and impersonate the victim, gaining access to the resources the victim is authorized to access.
The vulnerability stems from a lack of proper CSRF protection in Doorkeeper versions prior to 1.4.1. Specifically, the application fails to validate the origin of requests when handling requests related to OAuth authorization codes. This allows an attacker to craft malicious requests that appear to originate from the legitimate user's browser, enabling them to read a user's OAuth authorization code. The root cause is likely a missing or inadequate implementation of CSRF tokens or origin validation within the code responsible for handling authorization code retrieval. This allows an attacker to trick a logged-in user into unknowingly triggering an action that exposes their authorization code, which can then be used to impersonate the user.
While no specific APT groups are directly linked to this CVE, the nature of the vulnerability makes it attractive to various threat actors. Any attacker seeking to gain unauthorized access to user accounts or data could exploit this vulnerability. The lack of specific attribution makes it difficult to pinpoint specific actors. This vulnerability is not listed on the CISA KEV at the time of this report, but the potential impact warrants consideration.
Monitor web server logs for unusual activity, such as a high volume of requests from a single IP address to authorization code retrieval endpoints.
Analyze HTTP request headers for missing or unexpected CSRF tokens or origin validation.
Implement and monitor a Web Application Firewall (WAF) to detect and block suspicious requests.
Review application source code for proper CSRF token implementation and validation.
Monitor network traffic for suspicious patterns related to OAuth authorization code retrieval.
Upgrade Doorkeeper to version 1.4.1 or later.
Implement robust CSRF protection mechanisms, including the use of unique, unpredictable CSRF tokens in all forms and requests that modify data.
Validate the Origin or Referer header in all requests to ensure they originate from the expected domain.
Regularly scan the application for vulnerabilities using static and dynamic analysis tools.
Implement a Web Application Firewall (WAF) to filter malicious requests.
Enforce secure coding practices and conduct regular security audits.