The import form CSRF vulnerability in MuraCMS through 10.1.10 allows attackers to upload and install malicious form definitions through a CSRF attack. The vulnerable cForm.importform function lacks CSRF token validation, enabling malicious websites to forge file upload requests that install attacker-controlled forms when an authenticated administrator visits a crafted webpage. Full exploitation of this vulnerability would require the victim to select a malicious ZIP file containing form definitions, which can be automatically generated by the exploit page and used to create data collection forms that steal sensitive information. Successful exploitation of the import form CSRF vulnerability could result in the installation of malicious data collection forms on the target MuraCMS website that can steal sensitive user information. When an authenticated administrator visits a malicious webpage containing the CSRF exploit and selects the attacker-generated ZIP file, their browser uploads and installs form definitions that create legitimate forms that could be designed with malicious content.
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]
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/111.html
- https://cwe.mitre.org/data/definitions/462.html
- https://cwe.mitre.org/data/definitions/467.html
- https://cwe.mitre.org/data/definitions/62.html