CVE-2023-27593 : Security Advisory and Response

This CVE record pertains to a vulnerability in the cilium-agent container that allows unauthorized access to the host via

hostPath

mount. The vulnerability has been assigned a base severity of MEDIUM and a CVSS score of 4.4.

Understanding CVE-2023-27593

This section provides an overview of CVE-2023-27593, highlighting the impact, technical details, and mitigation strategies associated with this vulnerability.

What is CVE-2023-27593?

The vulnerability in the cilium-agent container, prior to versions 1.11.15, 1.12.8, and 1.13.1, enables an attacker with access to a Cilium agent pod to write to

/opt/cni/bin

due to a

hostPath

mount of that directory. This allows the attacker to replace the CNI binary with a malicious one and potentially gain unauthorized access to the underlying node.

The Impact of CVE-2023-27593

The impact of this vulnerability is significant as it can lead to unauthorized access to the host system, compromising the integrity and security of the overall infrastructure. By exploiting this vulnerability, an attacker may escalate privileges and perform malicious activities on the affected systems.

Technical Details of CVE-2023-27593

In this section, we delve into specific technical details related to CVE-2023-27593, including the vulnerability description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The vulnerability arises from incorrect default permissions in the cilium-agent container, allowing unauthorized write access to sensitive directories and potentially leading to unauthorized system access.

Affected Systems and Versions

Versions < 1.11.15: Affected
Versions >= 1.12.0, < 1.12.8: Affected
Versions >= 1.13.0, < 1.13.1: Affected

Exploitation Mechanism

Attackers can exploit this vulnerability by gaining access to a Cilium agent pod and manipulating the

hostPath

mount to replace critical binaries with malicious ones, facilitating unauthorized access to the host system.

Mitigation and Prevention

This section outlines the necessary steps to mitigate the risks associated with CVE-2023-27593, ensuring the security and integrity of the affected systems.

Immediate Steps to Take

Upgrade to patched versions 1.11.15, 1.12.8, or 1.13.1 to address the vulnerability.
Implement Kubernetes RBAC to restrict users and service accounts from executing commands within Cilium agent pods.

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities promptly.
Conduct security audits and assessments to identify and remediate potential security flaws in the infrastructure.

Patching and Updates

Patch your Cilium deployment to versions 1.11.15, 1.12.8, or 1.13.1 to mitigate the vulnerability.
Stay informed about security advisories and updates from Cilium to address potential security risks proactively.