Simply Schedule Appointments <= 1.6.9.15 - Missing Authorization

This plan outlines the steps to identify and exploit the "Missing Authorization" vulnerability (CVE-2025-69315) in the Simply Schedule Appointments (SSA) plugin. Since the vulnerability involves an unauthenticated "unauthorized action," our research will focus on identifying AJAX or REST API endpoints that are exposed to logged-out users but perform administrative or sensitive state-changing operations.

1. Vulnerability Summary

The Simply Schedule Appointments plugin (up to 1.6.9.15) contains one or more functions that lack appropriate capability checks (current_user_can()). While these functions perform sensitive actions (e.g., modifying appointments, changing settings, or administrative cleanup), they are accessible to unauthenticated users via wp_ajax_nopriv_* hooks or REST API routes with permission_callback set to __return_true.

2. Attack Vector Analysis

• Endpoint: wp-admin/admin-ajax.php (for AJAX actions) or wp-json/ssa/v1/... (for REST routes).
• Action Type: Unauthorized state modification (Integrity: Low/Medium).
• Authentication: None required (unauthenticated).
• Preconditions: The plugin must be active. Some exploits may require a valid Appointment ID or a localized nonce found on the frontend booking page.

3. Code Flow (Discovery Phase)

The agent must first identify the specific vulnerable function by analyzing the hook registrations.

Step A: Identify Potential Entry Points
Search for AJAX actions that are registered for both logged-in and logged-out users:

grep -r "wp_ajax_nopriv_" . | grep "ssa_"

Step B: Analyze Callbacks
For each identified action (e.g., ssa_cancel_appointment, ssa_dismiss_notice, ssa_update_appointment_status), trace the callback function.

1. Locate the function definition.
2. Check for the absence of:
   • current_user_can( 'manage_options' )
   • current_user_can( 'edit_posts' )
   • Appropriate ownership checks (e.g., verifying a "customer secret token" matches the appointment).

Step C: Target Identification
Focus on actions that modify data. A likely candidate in SSA is the appointment cancellation or status update logic if it fails to verify the request's origin or ownership.

4. Nonce Acquisition Strategy

SSA typically localizes nonces and API configuration into a JavaScript object. To obtain a nonce for an unauthenticated request:

1. Identify Trigger: The booking scripts (and nonces) are usually enqueued on pages containing the SSA booking shortcode.
2. Create Test Page:

   wp post create --post_type=page --post_status=publish --post_title="Booking" --post_content='[ssa_booking]'
   

3. Extract Nonce via Browser:
   • Navigate to the newly created page.
   • Use browser_eval to find the SSA data object.
   • Common SSA JS Objects (inferred): window.ssa_booking_data, window.ssa_public, or window.ssa_params.
   • JS Command: browser_eval("window.ssa_booking_data?.nonce || window.ssa_params?.nonce") (The agent must verify the exact key by inspecting the page source).

5. Exploitation Strategy

Assuming the vulnerability is in an AJAX action named ssa_unauthorized_action (placeholder):

• Request URL: http://<target>/wp-admin/admin-ajax.php
• Method: POST
• Headers: Content-Type: application/x-www-form-urlencoded
• Payload:

  action=ssa_unauthorized_action&nonce=[EXTRACTED_NONCE]&appointment_id=1&new_status=cancelled
  

6. Test Data Setup

1. Install SSA: Ensure version 1.6.9.15 is installed.
2. Create Appointment: Create a legitimate appointment as an admin or guest so there is an ID to target.

   # (Example using SSA CLI if available, or manually via UI/REST)
   # Note: Use the plugin UI to create a test appointment and note the ID.
   

3. Place Shortcode: Ensure the [ssa_booking] shortcode is on a public page to facilitate nonce extraction.

7. Expected Results

• Vulnerable Response: The server returns a success code (e.g., {"success": true} or 200 OK) and the targeted data (appointment status, setting, etc.) is modified.
• Blocked Response: The server returns 403 Forbidden, 0, or an error message indicating insufficient permissions.

8. Verification Steps

After the exploit, use wp-cli to verify the unauthorized change:

1. Check Appointment Status:

   wp db query "SELECT status FROM wp_ssa_appointments WHERE id = 1;"
   

2. Check Plugin Options (if settings were targeted):

   wp option get ssa_settings
   

9. Alternative Approaches

If no wp_ajax_nopriv hooks look promising, investigate the REST API:

1. List SSA REST routes:

   wp rest route list | grep "ssa"
   

2. Inspect the permission_callback for routes that handle POST, PUT, or DELETE requests. Look for callbacks that simply return true.
3. Test these routes using the http_request tool, providing the X-WP-Nonce header if required (obtained from the frontend via ssa_booking_data.rest_nonce).

10. Direct File Access Check

In case the "unauthorized action" is a direct access issue, check for files in includes/ that do not have the ABSPATH check:

for f in $(find . -name "*.php"); do
    if ! grep -q "ABSPATH" "$f"; then
        echo "Missing ABSPATH: $f"
    fi
done

Verify if these files perform any logic when accessed directly.