CVE-2019-11255 : What You Need to Know

Kubernetes CSI volume snapshot, cloning, and resizing features can result in unauthorized volume data access or mutation.

Understanding CVE-2019-11255

What is CVE-2019-11255?

The vulnerability involves improper input validation in Kubernetes CSI sidecar containers, potentially leading to unauthorized access or modification of PersistentVolume data during various operations.

The Impact of CVE-2019-11255

The vulnerability could allow unauthorized access to PersistentVolume data or unauthorized modification of volumes during operations like snapshot creation, restoration from snapshot, cloning, and resizing.

Technical Details of CVE-2019-11255

Vulnerability Description

The validation of input in Kubernetes CSI sidecar containers for external-provisioner, external-snapshotter, and external-resizer is not done correctly, leading to potential security risks.

Affected Systems and Versions

kubernetes-csi external-provisioner: Prior to 1.0.2, 1.1, prior to 1.2.2, prior to 1.3.1, and v1.14 prior to 0.4.3
kubernetes-csi external-snapshotter: Prior to 0.4.2, prior to 1.0.2, 1.1, prior to 1.2.2
kubernetes-csi external-resizer: 0.1, 0.2

Exploitation Mechanism

The vulnerability arises due to incorrect input validation in the Kubernetes CSI sidecar containers, allowing unauthorized access or modification of volume data.

Mitigation and Prevention

Immediate Steps to Take

Disable Kubernetes feature gates and revoke RBAC permissions from impacted CSI drivers.

Long-Term Security Practices

Regularly update Kubernetes and associated components.
Implement strong RBAC policies and access controls.
Monitor for unauthorized access or modifications.

Patching and Updates

Stay informed about security releases and apply relevant patches promptly.