A recently discovered vulnerability, CVE-2022-45933, in KubeView through version .1.31 has raised significant alarm amongst Kubernetes administrators. This vulnerability allows attackers to gain control of a Kubernetes cluster because of a missing authentication mechanism in the api/scrape/kube-system function. The exploit not only permits unauthorized access to the cluster, but also retrieves sensitive certificate files that can be used for further malicious activities.

In this post, we will provide an overview of the vulnerability, share code snippets to help you understand the issue, and reference the original sources for more information. It is crucial to act promptly and secure your systems against this vulnerability. Please note that the vendor has acknowledged the security issue and stated that KubeView is not intended as a secure application, but rather a "fun side project and a learning exercise."

Vulnerability Details

KubeView is a web-based application that visualizes the structure and components of a Kubernetes cluster. Unfortunately, the api/scrape/kube-system endpoint in the application does not require any form of authentication. This means that an attacker could use it to retrieve certificate files and authenticate themselves as a kube-admin without proper privileges.

The attack scenario could look like this

1. An attacker discovers an exposed instance of KubeView running on a Kubernetes cluster, which is accessible on the internet or within a network.
2. The attacker sends an unauthenticated request to the api/scrape/kube-system endpoint.

Here's a simple example of exploiting this vulnerability using Python

import requests

# Replace this with the target KubeView URL
kubeview_url = "http://example.com";

# Send an unauthenticated request to the api/scrape/kube-system endpoint
response = requests.get(f"{kubeview_url}/api/scrape/kube-system")

# Check if the response contains the expected certificates
if "kube-ca.pem" in response.text and "kube-admin.pem" in response.text:
    print("Vulnerable system detected. Certificate files obtained.")
else:
    print("System not vulnerable or response data not as expected.")

References and Further Reading

For those interested in learning more about this vulnerability and following the latest updates, we recommend visiting:

1. CVE details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-45933
2. KubeView GitHub Repository: https://github.com/benc-uk/kubeview
3. Vendor's statement on the vulnerability: https://github.com/benc-uk/kubeview/discussions/153

Mitigation and Recommendations

Considering the vendor's position that KubeView is not a "very secure" application and intended as a learning project, its use in production or sensitive environments is not recommended. However, if you need to continue using KubeView, please take the following steps:

Ensure that KubeView is not publicly accessible on the internet or within untrusted networks.

2. Restrict access to KubeView by implementing network-based access controls, such as firewall rules or a VPN.

Conclusion

CVE-2022-45933 is a critical vulnerability affecting KubeView through version .1.31. Since the application lacks proper authentication and exposes sensitive data to attackers, its use in secure environments is not advisable. Administrators should review their infrastructure and ensure both adequate security for their Kubernetes clusters and proper access control surrounding any use of KubeView.

Timeline

Published on: 11/27/2022 03:15:00 UTC
Last modified on: 12/01/2022 18:41:00 UTC