CVE-2023-41931: Jenkins Job Configuration History Plugin XSS Vulnerability Affecting Versions 1227.v7a_79fc4dc01f and Earlier

The Jenkins Job Configuration History Plugin is widely used as it allows users to keep track of their job configuration changes, store the previous state of a job configuration, and easily revert to a previous configuration if necessary. However, version 1227.v7a_79fc4dc01f and earlier of this plugin contain a significant security vulnerability: the plugin does not properly sanitize or escape the timestamp value from history entries when rendering a history entry on the history view, resulting in a stored cross-site scripting (XSS) vulnerability.

This blog post will provide an in-depth analysis of the CVE-2023-41931 vulnerability, including code snippets, links to original references, and exploit details.

Vulnerability Details

Jenkins Job Configuration History Plugin fails to properly sanitize or escape the timestamp value of the history entries. This can be exploited to execute arbitrary HTML and JavaScript code in the context of the user's browser when they view a history entry. The issue lies within the handling of the timestamp value from the history entries in the file getJobConfigHistoryList.jelly. The following code snippet demonstrates the issue:

<table>
  <tr>
    <td>Timestamp</td>
    <td><j:out value="${it.timestamp}"/></td>
  </tr>
  ...
</table>

The code above directly outputs the raw value of it.timestamp without any sanitization or escaping, allowing an attacker to inject arbitrary HTML and JavaScript code.

Exploit

To exploit this vulnerability, an attacker must first create a malicious history entry with a specially crafted timestamp value. Such an entry may contain JavaScript code that will be executed when a user views the history entry. For instance, an attacker can inject the following code as the timestamp value:

<script>alert('XSS');</script>

When a user views the history entry with this timestamp, the JavaScript code will be executed, displaying an alert with the text 'XSS'. This is a simple example, but the attacker could potentially execute more sophisticated and harmful scripts.

Mitigation

Users running Jenkins Job Configuration History Plugin version 1227.v7a_79fc4dc01f and earlier should immediately update to the latest version of the plugin, which contains a fix for this vulnerability. The updated version properly sanitizes and escapes the timestamp value before rendering the history entry:

<table>
  <tr>
    <td>Timestamp</td>
    <td><j:out value="${h.escape(it.timestamp)}"/></td>
  </tr>
  ...
</table>

The h.escape() function ensures that the timestamp value is correctly sanitized and escaped, preventing the execution of any malicious code.

References

1. CVE-2023-41931 - Jenkins Security Advisory
2. Jenkins Job Configuration History Plugin
3. Jenkins Issue: Jenkins Job Configuration History Plugin Stored XSS

Conclusion

The CVE-2023-41931 vulnerability demonstrates the importance of properly sanitizing and escaping user input when rendering web views. Jenkins Job Configuration History Plugin users should update to the latest version as soon as possible to protect themselves from potential exploits. Always be vigilant in applying good security practices and following security advisories to ensure the safety of your systems.

Timeline

Published on: 09/06/2023 13:15:09 UTC
Last modified on: 09/11/2023 19:55:42 UTC