CVE-2023-3893 : Security Advisory and Response

This CVE record was assigned by Kubernetes and published on November 3, 2023. The vulnerability affects Kubernetes clusters that include Windows nodes running kubernetes-csi-proxy, potentially allowing a user to escalate their privileges to admin level on those nodes.

Understanding CVE-2023-3893

This section delves into the specifics of CVE-2023-3893, highlighting its impact, technical details, affected systems, exploitation mechanism, and mitigation strategies.

What is CVE-2023-3893?

CVE-2023-3893 is a security issue in Kubernetes where an attacker with the ability to create pods on Windows nodes running kubernetes-csi-proxy can potentially escalate their privileges to admin level on those nodes. This vulnerability is critical as it can lead to unauthorized access and control within Kubernetes clusters.

The Impact of CVE-2023-3893

The impact of CVE-2023-3893 is classified under CAPEC-233 (Privilege Escalation). It poses a high risk to the confidentiality, integrity, and availability of the affected systems, with a CVSS v3.1 base severity score of 8.8 (High).

Technical Details of CVE-2023-3893

This section provides an overview of the technical aspects of CVE-2023-3893, including the vulnerability description, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

The vulnerability stems from insufficient input sanitization in kubernetes-csi-proxy, allowing an attacker to exploit this weakness to gain elevated privileges on Windows nodes within Kubernetes clusters.

Affected Systems and Versions

Kubernetes clusters with Windows nodes running kubernetes-csi-proxy versions v2.0.0-alpha.0 and below, as well as v1.1.2 and below, are susceptible to this privilege escalation vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by leveraging the lack of proper input validation in kubernetes-csi-proxy to manipulate pod creation on Windows nodes and escalate their privileges to admin access.

Mitigation and Prevention

To safeguard systems against CVE-2023-3893 and prevent potential exploitation, it is essential to take immediate steps, implement long-term security practices, and apply necessary patches and updates.

Immediate Steps to Take

Disable pod creation privileges for untrusted users on Windows nodes.
Regularly monitor and audit pod activities on Kubernetes clusters.
Implement access controls and restrictions to limit unauthorized privileges.

Long-Term Security Practices

Conduct regular security assessments and audits to identify and address vulnerabilities promptly.
Provide security awareness training for personnel handling Kubernetes clusters.
Stay informed about security advisories and best practices recommended by Kubernetes and related vendors.

Patching and Updates

Ensure that all affected systems are updated with the latest patches and fixes provided by Kubernetes for the kubernetes-csi-proxy component. Regularly check for security advisories and apply updates promptly to mitigate the risk of privilege escalation exploits.