Salon Booking System Cross-site Scripting

Cross-site scripting vulnerability in Salon booking system versions prior to 7.9 allows a remote unauthenticated attacker to inject an arbitrary script. (2022-12-05, CVE-2022-43487)

The Salon booking system WordPress plugin before 6.3.1 does not properly sanitise and escape the First Name field when booking an appointment, allowing low privilege users such as subscriber to set JavaScript in them, leading to a Stored Cross-Site Scripting (XSS) vulnerability. The Payload will then be triggered when an admin visits the "Calendar" page and the malicious script is executed in the admin context. (2021-07-12, CVE-2021-24429)

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>