In the ever-evolving world of web applications, security vulnerabilities are a significant concern, and here is one that demands our attention. A Cross-Site Request Forgery (CSRF) vulnerability (CVE-2023-40336) has been discovered in Jenkins Folders Plugin 6.846.v23698686ff6 and earlier versions. This vulnerability allows attackers to exploit the plugin and copy folders without the user's knowledge.

What is Cross-Site Request Forgery (CSRF)?

Cross-Site Request Forgery (CSRF) is a type of security vulnerability that tricks users into executing unintended actions on a web application while they are authenticated. Usually, this occurs because the application doesn't have proper measures in place to validate that a specific user intentionally initiated the action.

How the Vulnerability Works

The CSRF vulnerability (CVE-2023-40336) affects Jenkins Folders Plugin 6.846.v23698686ff6 and earlier versions, allowing attackers to send maliciously crafted requests to Jenkins' server and copy folders without any user awareness.

Here's an example code snippet to demonstrate how a malicious request can be crafted

<!DOCTYPE html>
<html>
  <body>
    <h1>Malicious CSRF Exploit</h1>
    <form action="https://jenkins.example.com/job/FolderToBeCopied/doCopy"; method="POST">
      <input type="hidden" name="destination" value="FolderCopyName" />
      <input type="submit" value="CLICK ME" />
    </form>
  </body>
</html>

In this example, the attacker creates a malicious HTML file or injects the above code into a web page visited by the Jenkins user. Once the user clicks the "CLICK ME" button, a POST request to the server is initiated, copying the specified folder without the user's consent.

Original Reference

The vulnerability was originally reported and documented by the Jenkins team and can be reviewed in their official security advisory.

Exploit Details

To exploit this vulnerability, an attacker needs to trick users into opening a malicious page similar to the example provided above. The attacker then convinces the user to click on a button or link that initiates an unsolicited request to the server. If the user is authenticated to the Jenkins server, the folder copy action will proceed without any further validation.

Take note that this exploit doesn't allow the attacker to create or modify the contents of the folder. However, unauthorized folder copying can unintentionally disclose sensitive information that may lead to further exploitation of the affected system.

Mitigation Measures

To protect against this vulnerability, users should immediately upgrade to Jenkins Folders Plugin version 6.847.v82b3c35c24de or later. This version provides a fix for the CSRF vulnerability by implementing a CSRF protection token, which effectively mitigates the risk of maliciously crafted requests.

You can download the latest version of Jenkins Folders Plugin from the official Jenkins plugin repository here.

In addition, it's recommended to educate users about secure browsing practices and the risks associated with clicking links from untrusted sources. This will help users recognize suspicious content and avoid falling victim to CSRF attacks.

Conclusion

The Cross-Site Request Forgery (CSRF) vulnerability (CVE-2023-40336) in Jenkins Folders Plugin 6.846.v23698686ff6 and earlier versions poses a security risk that allows attackers to exploit the system and perform unauthorized folder copying. By understanding this vulnerability, its exploit details, and taking the necessary mitigation measures, users can protect their Jenkins server from potential security breaches.

Timeline

Published on: 08/16/2023 15:15:00 UTC
Last modified on: 08/22/2023 18:43:00 UTC