The Fluent Forms Pro Add On Pack plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 6.1.17. This is due to the deleteFile() method in the Uploader class lacking nonce verification and capability checks. The AJAX action is registered via addPublicAjaxAction() which creates both wp_ajax_ and wp_ajax_nopriv_ hooks. This makes it possible for unauthenticated attackers to delete arbitrary WordPress media attachments via the attachment_id parameter.
Note: The researcher described file deletion via the path parameter using sanitize_file_name(), but the actual code uses Protector::decrypt() for path-based deletion which prevents exploitation. The vulnerability is exploitable via the attachment_id parameter instead.
Weakness
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Potential Mitigations
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.
- Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
- One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.