Core Cross-site Scripting

An issue was discovered in Form Tools through 3.0.20. A low-privileged user can trigger Reflected XSS when a viewing a form via the submission_id parameter, e.g., clients/forms/edit_submission.php?form_id=1&view_id=1&submission_id=[XSS]. (2021-08-31, CVE-2021-38144)

An issue was discovered in Form Tools through 3.0.20. When an administrator creates a customer account, it is possible for the customer to log in and proceed with a change of name and last name. However, these fields are vulnerable to XSS payload insertion, being triggered in the admin panel when the admin tries to see the client list. This type of XSS (stored) can lead to the extraction of the PHPSESSID cookie belonging to the admin. (2021-08-31, CVE-2021-38143)

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>