Schedula <= 1.0 - Missing Authorization

This research plan targets CVE-2025-67970, a missing authorization vulnerability in the Schedula – Smart Appointment Booking plugin (version <= 1.0).

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1. Vulnerability Summary

The Schedula plugin fails to implement capability checks (e.g., current_user_can()) in one or more of its AJAX or initialization handlers. This allows unauthenticated users to trigger functions intended for administrators or specific booking owners. Specifically, the vulnerability likely resides in an AJAX handler registered with both wp_ajax_ and wp_ajax_nopriv_ that performs data modification (like deleting or updating bookings) without verifying the user's permissions or ownership of the record.

2. Attack Vector Analysis

• Endpoint: wp-admin/admin-ajax.php
• Action: To be determined via discovery (likely schedula_delete_booking, schedula_cancel_appointment, or schedula_update_status).
• Method: HTTP POST
• Authentication: None (Unauthenticated)
• Preconditions: A valid appointment/booking must exist in the database for the attacker to target. A valid WordPress nonce for the specific action may be required.

3. Code Flow Trace

1. Entry Point: The plugin registers AJAX hooks in the main plugin file or an inclusion file (e.g., includes/class-schedula-ajax.php).
   • Grep Search: grep -rn "wp_ajax_nopriv_" .
2. Hook Registration: Look for lines like:
   add_action( 'wp_ajax_nopriv_ACTION_NAME', array( $this, 'FUNCTION_NAME' ) );
3. Vulnerable Function: The FUNCTION_NAME is called.
4. Missing Check: Inside FUNCTION_NAME, the code likely processes $_POST['id'] and performs a database operation (e.g., $wpdb->delete or wp_delete_post) without calling current_user_can('manage_options').
5. Sink: The database is modified, or a sensitive setting is updated.

4. Nonce Acquisition Strategy

If the vulnerable handler uses check_ajax_referer or wp_verify_nonce, the attacker must retrieve a valid nonce.

1. Identify Shortcode: Find the shortcode that renders the booking interface (likely [schedula_booking_form] or [schedula_manage_bookings]).
   • Grep Search: grep -rn "add_shortcode" .
2. Setup Page: Create a public page containing this shortcode:
   wp post create --post_type=page --post_title="Booking" --post_status=publish --post_content='[shortcode_found]'
3. Browser Extraction:
   • Navigate to the newly created page using browser_navigate.
   • Use browser_eval to inspect the JavaScript environment for localized data.
   • Common variable names (inferred): schedula_vars, schedula_ajax, schedula_obj.
   • Extraction Command: browser_eval("window.schedula_vars?.nonce") or similar.

5. Exploitation Strategy

Once the action and nonce are identified:

1. Identify Target ID: Create an appointment to find its ID (e.g., ID 123).
2. Construct Payload:
   • URL: http://localhost:8080/wp-admin/admin-ajax.php
   • Content-Type: application/x-www-form-urlencoded
   • Body: action=ACTION_NAME&id=123&security=NONCE_VALUE (Parameter names like id and security are inferred and must be verified from source).
3. Execute: Use http_request to send the POST payload.
4. Observe Response: A successful exploit often returns a JSON success: true or a 1 (for standard AJAX handlers).

6. Test Data Setup

1. Install Plugin: Ensure Schedula version 1.0 is installed.
2. Create Appointment: Use the plugin's frontend or admin interface to create at least one appointment.
3. Identify ID: Use wp post list --post_type=schedula_booking (if it's a Custom Post Type) or wp db query "SELECT id FROM wp_schedula_bookings" to find the ID of the created appointment.
4. Public Page: Create the page with the shortcode as described in Section 4.

7. Expected Results

• HTTP Response: 200 OK with a body indicating success (e.g., {"success":true}).
• Database Change: The appointment with the targeted ID is either deleted from the database or its status is changed (e.g., from 'confirmed' to 'cancelled').
• Unauthorized Access: The action completes despite the request being sent without any authentication cookies.

8. Verification Steps

1. Database Check:
   • wp db query "SELECT * FROM wp_schedula_bookings WHERE id=123"
   • Verify that the record no longer exists or the status has changed.
2. Admin UI Check: Log in as admin and verify the appointment is missing from the Schedula dashboard.

9. Alternative Approaches

• Settings Modification: If the missing authorization is in an admin_init hook, the exploit would involve sending a POST request to admin-ajax.php with parameters to update WordPress options (e.g., schedula_settings[allow_registration]=1).
• Information Disclosure: If the action is a "fetch" action, the response body might contain sensitive customer information (names, emails) for all bookings, which would change the CVSS from I:L to C:L/H.
• Action Discovery: If grep fails, use browser_navigate to the booking page and use the "Network" tab equivalent or browser_eval to find jQuery.post calls in the plugin's JS files to identify the action string.