Blackcat Cms Cross-site Scripting

A stored cross site scripting (XSS) vulnerability in the 'Add Page' feature of BlackCat CMS 1.3.6 allows authenticated attackers to execute arbitrary web scripts or HTML via a crafted payload entered into the 'Title' parameter. (2021-07-09, CVE-2020-25877)

A stored cross site scripting (XSS) vulnerability in the 'Admin-Tools' feature of BlackCat CMS 1.3.6 allows authenticated attackers to execute arbitrary web scripts or HTML via crafted payloads entered into the 'Output Filters' and 'Droplets' modules. (2021-07-09, CVE-2020-25878)

The admin panel in BlackCat CMS 1.3.6 allows stored XSS (by an admin) via the Display Name field to backend/preferences/ajax_save.php. (2021-02-16, CVE-2021-27237)

Blackcat CMS 1.3.2 allows XSS via the willkommen.php?lang=DE page title at backend/pages/modify.php. (2018-12-10, CVE-2018-16635)

Cross-site scripting (XSS) vulnerability in backend/pages/modify.php in BlackCatCMS 1.3 allows remote authenticated users with the Admin role to inject arbitrary web script or HTML via the search panel. (2018-06-14, CVE-2018-10821)

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>