CVE-2023-41537 - Exploiting XSS in phpjabbers Business Directory Script 3.2 via the “keyword” Parameter

In September 2023, a critical vulnerability (CVE-2023-41537) was reported in the phpjabbers Business Directory Script version 3.2. This issue allows attackers to execute Cross Site Scripting (XSS) via the keyword parameter found on the business search page. In this post, we’ll break down what this vulnerability is, how it works, and provide a hands-on example showing how it could be exploited.

What is phpjabbers Business Directory Script?

phpjabbers Business Directory Script is a popular PHP-based web application that enables businesses to create and manage an online directory. It’s often used for sites listing local businesses, professionals, or any kind of searchable directory. With a reported easy install and good customizability, it’s widely used among small business owners and webmasters.

What is CVE-2023-41537?

CVE-2023-41537 is a vulnerability where the script fails to sanitize user input from the keyword parameter in search queries. This failure to handle potentially malicious input properly results in a Stored/XSS vulnerability. That means attackers can inject JavaScript (or other client-side code) that runs in other users’ browsers. This can be used to steal sessions, impersonate users, or perform actions on behalf of other users.

Vulnerable Code Example

The vulnerable code is found in the file that handles directory searches, typically index.php or a similar entry point. When a user submits a search through the site’s search form, the application collects the keyword parameter and outputs it directly in the HTML response, without properly escaping it.

Here is a simplified code snippet (for educational purposes only)

// This processes the search query
if (isset($_GET['keyword'])) {
    $keyword = $_GET['keyword'];
    echo "<div>Search Results for: $keyword</div>"; // UNSAFE
    // ... rest of search logic ...
}

The problem here is that $keyword is directly placed into the HTML page. If someone passes a string like <script>alert('XSS');</script>, it will be embedded and executed by browsers visiting the search results page.

`plaintext

https://victim.com/directory/index.php?keyword=%3Cscript%3Ealert('XSS')%3C/script%3E

`

Here %3Cscript%3Ealert('XSS')%3C/script%3E is just URL-encoded <script>alert('XSS')</script>.

Sending the Link:

Script Execution:

When a victim clicks the link, their browser visits the page and executes the embedded JavaScript code (in this case, alert('XSS')).

What users see:

!XSS Pop-Up Illustration

How to Fix

The best way to resolve this is to always sanitize and escape all user input before rendering it in the application output.

Change this

echo "<div>Search Results for: $keyword</div>";

To this

echo "<div>Search Results for: " . htmlspecialchars($keyword, ENT_QUOTES, 'UTF-8') . "</div>";

The htmlspecialchars() function converts special characters into HTML entities, which prevents browsers from interpreting malicious code.

Responsible Disclosure & References

The issue has been reported and assigned as CVE-2023-41537.

Conclusion

CVE-2023-41537 is a simple but dangerous XSS vulnerability in phpjabbers Business Directory Script 3.2, triggered via the keyword parameter. As a website owner or developer using this product, upgrade your scripts and always sanitize user input.

Remember: Never trust user input. Always escape output.

Stay safe out there!

*(This post is for educational and awareness purposes only. Always test in safe environments and follow coordinated disclosure practices.)*

Timeline

Published on: 08/30/2023 14:15:10 UTC
Last modified on: 08/31/2023 21:06:11 UTC