Hello everyone,

Today, I would like to explore the details of a critical security vulnerability discovered in the popular Jenkins Gogs Plugin version 1..15 and earlier. The vulnerability, identified as CVE-2023-40348, allows unauthenticated attackers to gather sensitive information about the existence of jobs in the plugin’s output, which could be potentially exploited for further attacks that target Jenkins. In this post, we will dive into the exploit details, share code snippets, and provide links to the original sources and references.

Exploit Details

The Jenkins Gogs Plugin provides seamless integration between Jenkins and the Gogs repository, allowing developers to build, test, and deploy code effortlessly. However, this webhook integration can be exploited due to its insecure implementation in version 1..15 and earlier. Specifically, the webhook endpoint gives unauthenticated attackers access to details concerning the existence of jobs within the plugin's output. This information could potentially be used to compromise Jenkins and exploit other vulnerabilities in the system.

To better understand how this exploit works, let us examine a simple code snippet that demonstrates the vulnerability:

import requests

jenkins_url = "http://<jenkins_url>/gogs-webhook/";
response = requests.get(jenkins_url)

if response.status_code == 200:  # The server returns a 200 OK response when the exploit is successful.
    print(f"Found information about Jenkins jobs: {response.text}")

else:
    print("Unable to exploit Jenkins.")

As seen above, a simple GET request to the gogs-webhook endpoint retrieves the details about Jenkins jobs without any authentication required. This information is simply displayed within the output, potentially exposing sensitive data to attackers.

- Official CVE Details
- Jenkins Security Advisory
- NVD - National Vulnerability Database

To protect your Jenkins instance from this vulnerability, it is crucial to take the following steps

1. Upgrade to Jenkins Gogs Plugin version 1..16 or later. As of this plugin version, the issue has been fixed, and the webhook endpoint no longer leaks job information.
2. If upgrading is not an option, consider restricting access to the webhook endpoint by implementing a firewall or other network security measures to limit the exposure of Jenkins jobs data.

Conclusion

In conclusion, CVE-2023-40348 represents a critical security issue that exposes sensitive Jenkins job information to unauthenticated attackers. By exploiting this vulnerability, attackers can gather information about Jenkins jobs and potentially use this data to craft further attacks. It is essential to upgrade the Jenkins Gogs Plugin to version 1..16 or later to address this issue and secure your Jenkins instance properly.

Timeline

Published on: 08/16/2023 15:15:00 UTC
Last modified on: 08/18/2023 19:59:00 UTC