The Ninja Forms – The Contact Form Builder That Grows With You plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 3.13.2. This is due to the plugin not properly verifying that a user is authorized before the ninja-forms-views REST endpoints return form metadata and submission content. This makes it possible for unauthenticated attackers to read arbitrary form definitions and submission records via a leaked bearer token granted they can load any page containing the Submissions Table block. NOTE: The developer released a patch for this issue in 3.13.1, but inadvertently introduced a REST API endpoint in which a valid bearer token could be minted for arbitrary form IDs, making this patch ineffective.
The system’s authorization functionality does not prevent one user from gaining access to another user’s data or record by modifying the key value identifying the data.
Retrieval of a user record occurs in the system based on some key value that is under user control. The key would typically identify a user-related record stored in the system and would be used to lookup that record for presentation to the user. It is likely that an attacker would have to be an authenticated user in the system. However, the authorization process would not properly check the data access operation to ensure that the authenticated user performing the operation has sufficient entitlements to perform the requested data access, hence bypassing any other authorization checks present in the system. For example, attackers can look at places where user specific data is retrieved (e.g. search screens) and determine whether the key for the item being looked up is controllable externally. The key may be a hidden field in the HTML form field, might be passed as a URL parameter or as an unencrypted cookie variable, then in each of these cases it will be possible to tamper with the key value. One manifestation of this weakness is when a system uses sequential or otherwise easily-guessable session IDs that would allow one user to easily switch to another user’s session and read/modify their data.