Wordfence Security Cross-site Scripting

The Wordfence Security – Firewall & Malware Scan plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to and including 7.6.0 via a setting on the options page due to insufficient escaping on the stored value. This makes it possible for authenticated users, with administrative privileges, to inject malicious web scripts into the setting that executes whenever a user accesses a page displaying the affected setting on sites running a vulnerable version. (2022-09-23, CVE-2022-3144)

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>