CVE-2020-8558 : Security Advisory and Response

Kubernetes node setting allows for neighboring hosts to bypass localhost boundary.

Understanding CVE-2020-8558

The security issue in Kubernetes allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1, potentially accessible by other hosts on the same LAN.

What is CVE-2020-8558?

The Kubelet and kube-proxy components in specific versions of Kubernetes were found to have a vulnerability that could enable neighboring hosts to bypass the localhost boundary.

The Impact of CVE-2020-8558

This vulnerability could allow unauthorized access to services that are typically restricted to the local host, potentially leading to unauthorized network access.

Technical Details of CVE-2020-8558

Vulnerability Description

The issue in Kubernetes versions 1.1.0-1.16.10, 1.17.0-1.17.6, and 1.18.0-1.18.3 allows adjacent hosts to access services bound to 127.0.0.1.

Affected Systems and Versions

Affected versions include Kubernetes prior to 1.18.4, 1.17.7, 1.16.11, and earlier.

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Adjacent Network
Privileges Required: None
Scope: Unchanged

Mitigation and Prevention

Immediate Steps to Take

Update Kubernetes to version 1.18.4 or later to mitigate the vulnerability.
Monitor network traffic for any unauthorized access.

Long-Term Security Practices

Regularly update Kubernetes to the latest stable version.
Implement network segmentation to restrict access to critical services.

Patching and Updates

Apply security patches promptly to address known vulnerabilities in Kubernetes.