Simple Banner Cross-site Scripting

The Simple Banner plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `pro_version_activation_code` parameter in versions up to, and including, 2.11.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, including those without administrative capabilities when access is granted to those users, to inject arbitrary web scripts in page that will execute whenever a user role having access to "Simple Banner" accesses the plugin's settings. (2022-09-06, CVE-2022-2515)

The Simple Banner WordPress plugin before 2.12.0 does not properly sanitize its "Simple Banner Text" Settings allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed. (2022-08-22, CVE-2022-0446)

The Simple Banner WordPress plugin before 2.10.4 does not sanitise and escape one of its settings, allowing high privilege users such as admin to use Cross-Site Scripting payload even when the unfiltered_html capability is disallowed. (2021-08-23, CVE-2021-24574)

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>