This article is a part of our Vulnerability Database (back to index)
Cross-site Scripting occurrences in Starter Templates
On sites that also had the Elementor plugin for WordPress installed, it was possible for users with the edit_posts capability, which includes Contributor-level users, to import blocks onto any page using the astra-page-elementor-batch-process AJAX action. An attacker could craft and host a block containing malicious JavaScript on a server they controlled, and then use it to overwrite any post or page by sending an AJAX request with the action set to astra-page-elementor-batch-process and the url parameter pointed to their remotely-hosted malicious block, as well as an id parameter containing the post or page to overwrite. Any post or page that had been built with Elementor, including published pages, could be overwritten by the imported block, and the malicious JavaScript in the imported block would then be executed in the browser of any visitors to that page. (2021-11-17, CVE-2021-42360)
Why Cross-site Scripting can be dangerous
Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.
The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:
https://server.com/confirmation?message=Transaction+Complete
what results in:
<span>Confirmation: Transaction Complete</span>
In that case the message can be modified to become a valid Javascript code, e.g.:
https://server.com/confirmation?message=<script>dangerous javascript code here</script>
and it will be executed locally by the user's browser with full access to the user's personal application/browser data:
<span>Confirmation: <script>dangerous javascript code here</script></span>