FluxCP is a web-based Control Panel for rAthena servers written in PHP. A critical Cross-Site Request Forgery (CSRF) vulnerability exists in the FluxCP-based website template used by multiple rAthena/Ragnarok servers. State-changing POST endpoints accept browser-initiated requests that are authorized solely by the session cookie without per-request anti-CSRF tokens or robust Origin/Referer validation. An attacker who can lure a logged-in user to an attacker-controlled page can cause that user to perform sensitive actions without their intent. This vulnerability is fixed with commit e3f130c.
Weakness
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
Potential Mitigations
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
- For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330]
- Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
- Use the “double-submitted cookie” method as described by Felten and Zeller:
- When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user’s machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same.
- Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult.
- This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]
References