Spiffy Calendar <= 5.0.7 - Missing Authorization

This research plan outlines the steps to analyze and exploit the Missing Authorization vulnerability (CVE-2025-68523) in the Spiffy Calendar plugin for WordPress.

1. Vulnerability Summary

The Spiffy Calendar plugin (<= 5.0.7) fails to perform adequate capability checks on certain administrative functions. Specifically, handlers registered for AJAX actions or admin_init hooks lack current_user_can() checks. This allows authenticated users with low-level privileges (Contributor and above) to execute actions intended only for Administrators, such as modifying plugin settings or managing calendar data.

2. Attack Vector Analysis

• Endpoint: /wp-admin/admin-ajax.php or /wp-admin/admin.php (depending on whether the handler is AJAX or admin_init based).
• Vulnerable Action: Likely spiffy_calendar_save_settings, spiffy_calendar_import_events, or spiffy_calendar_delete_event.
• Authentication: Authenticated session required (Contributor role).
• Parameter: The action parameter triggers the vulnerable function. Payload data is usually passed via $_POST.
• Precondition: The attacker must be logged in as a Contributor.

3. Code Flow (Inferred)

1. Registration: The plugin registers an action handler, for example:
   add_action('wp_ajax_spiffy_calendar_save_settings', 'spiffy_calendar_save_settings_callback');
2. Entry Point: A Contributor user sends a POST request to admin-ajax.php with action=spiffy_calendar_save_settings.
3. Execution: The spiffy_calendar_save_settings_callback() function is invoked.
4. The Bug: The function may call check_ajax_referer() (checking the nonce) but fails to call current_user_can('manage_options'). Since Contributors are "authenticated," the wp_ajax_ hook triggers, and the function executes administrative logic.

4. Nonce Acquisition Strategy

If the endpoint verifies a nonce, it is likely localized for the WordPress admin dashboard. Since a Contributor has access to /wp-admin/, they can extract it.

1. Identify Variable: Look for wp_localize_script in the plugin source (likely in includes/admin.php or the main plugin file).
   • Target JS Variable: spiffy_cal_admin_vars (inferred) or spiffy_calendar_vars (inferred).
   • Target Key: nonce or security.
2. Access Admin: Navigate to the Spiffy Calendar settings page (even if content is restricted, the script may load) or the main Dashboard.
3. Extraction:
   • Use browser_navigate to /wp-admin/admin.php?page=spiffy-calendar.
   • Use browser_eval to grab the nonce:
     browser_eval("window.spiffy_cal_admin_vars?.nonce")

5. Exploitation Strategy

This plan focuses on modifying a global plugin setting (e.g., the "Calendar Title" or "Time Format") to demonstrate unauthorized modification.

Step 1: Discover the vulnerable action

Check the plugin source for AJAX actions.

grep -r "wp_ajax_" wp-content/plugins/spiffy-calendar/

Look for actions that perform "Save" or "Update" operations.

Step 2: Formulate the Payload

Assuming the action is spiffy_calendar_save_settings:

• URL: http://localhost:8080/wp-admin/admin-ajax.php
• Method: POST
• Headers: Content-Type: application/x-www-form-urlencoded
• Body: action=spiffy_calendar_save_settings&nonce=[NONCE]&spiffy_calendar_title=Hacked+by+Contributor

Step 3: Execution

Use http_request with the Contributor's cookies to send the payload.

6. Test Data Setup

1. Install Plugin: Ensure Spiffy Calendar 5.0.7 is active.
2. Create User:

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

3. Initial State: Note the current calendar settings.

   wp option get spiffy_calendar_options
   

7. Expected Results

• The server should return a 200 OK or a JSON success response (e.g., {"success":true}).
• The plugin settings in the database should be updated despite the user only having Contributor privileges.

8. Verification Steps

1. Check Database:

   wp option get spiffy_calendar_options
   

   Verify if the spiffy_calendar_title (or chosen setting) has changed to the payload value.
2. Frontend Check: Visit the calendar page and check if the title has changed.

9. Alternative Approaches

If the vulnerability is in a function hooked to admin_init:

1. The attacker would send a request to a standard admin URL like wp-admin/admin.php?page=spiffy-calendar&action=reset_settings.
2. This often uses admin-post.php logic. Check for add_action('admin_post_...') or direct checks for $_POST['spiffy_calendar_import'] inside an admin_init hook.
3. If spiffy_calendar_import is the target, prepare a malicious CSV file and use http_request to POST it with multipart/form-data.