Terms Before Download
Terms Before Download is a WordPress plugin that shows a popup dialog with terms and conditions (EULA) that must be accepted before a file can be downloaded.
Its most important features are:
- The terms and conditions are read from a WordPress page. That way there is only a single place to maintain the terms and they can easily be displayed independently of the plugin.
- It supports Google Analytics to keep track of the number of downloads.
- It is highly customizable.
The plugin is available in the official wordpress.org plugin directory. You can try it out here.
This is what the plugin looks like:
5 Comments
Hallo Helge,
Dein wunderbares Plugin “Terms Before Download” wird als Sicherheitsrisiko erkannt, es scheint dass es möglich ist es für Cross Site Scripting irgendwie einsetzen. Denkst Du, dass Du es Update wirst und den Bug fixen?
Ich freue mich über eine kurze Rückmeldung.
Viele Grüße,
Enric
https://patchstack.com/database/wordpress/plugin/terms-before-download/vulnerability/wordpress-terms-before-download-plugin-1-0-4-cross-site-scripting-xss-vulnerability?_s_id=cve
I need more details.
I have no good coding skills, but here is what I got as output using AI to analyze the code. If this is really all, it is an easy fix, the AI states that just in some place input is not sanitized, which triggers the warning I got from my WordPress security software and which can also be found on the above linked URL, likely the place where this informtion came initially from.
Here is what I got:
The identified vulnerability in the WordPress plugin Terms Before Download can be attributed to the way user inputs, particularly concerning the dialog setup, are handled. The plugin is vulnerable to Cross Site Scripting (XSS) attacks due to improper sanitization of the content that is displayed in the dialog.
Problem Identification:
Dialog HTML Construction: In the shortcode_handler_tbd_terms function, the terms page content fetched via get_post and processed through do_shortcode() does not have sufficient sanitization applied before it is displayed in the dialog .
Potential Injection Point: Specifically, during dialog content preparation, the content could be manipulated if a malicious user manages to insert an attack vector in the terms_page content that is stored and later rendered on the site. As the dynamically generated script does not sanitize HTML context appropriately, this presents an XSS risk.
Recommended Fix:
To mitigate this XSS vulnerability, the encoding of client inputs, particularly within the construction of the dialog box where the terms content is displayed, must be handled correctly:
Sanitization Layer: Implement WordPress’s built-in sanitization functions to ensure that any potentially harmful input is neutralized.
Before setting $terms_page_content, use wp_kses_post() to sanitize the fetched content:
$terms_page_content = wp_kses_post(do_shortcode($terms_page->post_content));
This change will ensure that any untrusted content, particularly JavaScript or HTML injections, are effectively filtered out before rendering, thereby preventing XSS attacks when an admin or contributor attempts to view or interact with the terms displayed.
By applying these changes, you will significantly improve the security posture of the plugin against XSS vulnerabilities.
I have changed the line as described above and tested the plugin, it seems to work just fine.
Thanks for the details and for testing the fix suggested by AI. I also tested it and I can confirm that it doesn’t seem to cause any issues.
An updated version with this change, 1.0.5, was just published on WordPress.org. It’s also live on this site.