Poddycast Cross-site Scripting

Poddycast is a podcast app made with Electron. Prior to version 0.8.1, an attacker can create a podcast or episode with malicious characters and execute commands on the client machine. The application does not clean the HTML characters of the podcast information obtained from the Feed, which allows the injection of HTML and JS code (cross-site scripting). Being an application made in electron, cross-site scripting can be scaled to remote code execution, making it possible to execute commands on the machine where the application is running. The vulnerability is patched in Poddycast version 0.8.1. (2021-08-03, CVE-2021-32772)

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>