Kubernetes Security Announcement - v1.6.0-v1.6.5 Azure Persistent Disk Issue fixed in v1.6.6
Brandon Philips
Kubernetes Security Announcement
v1.6.0-v1.6.5 Azure Persistent Disk Issue fixed in v1.6.6
A vulnerability has been disclosed in which default access permissions for Persistent Volumes (PVs) created by the Kubernetes Azure cloud provider in versions 1.6.0 to 1.6.5 are set to "container" which exposes a URI that can be accessed without authentication on the public internet. Access to the URI string requires privileged access to the Kubernetes cluster or authenticated access to the Azure portal.
The vulnerability is tracked in http://issue.k8s.io/47611, and fixed in release v1.6.6, available immediately. The fix is also included in the upcoming 1.7.0 release.
Who is affected?
Only Kubernetes 1.6.0-1.6.5 installations that have Persistent Volumes (PVs) actively provisioned through the Azure cloud provider are subject to the vulnerability. Clusters without PVs are unaffected. No other form of cluster storage is impacted.
What is the impact?
An individual with the full URI of an actively provisioned persistent volume can download the VHD file for that volume. It does not apply retroactively to volumes already deleted from the cluster.
How can I mitigate this prior to installing 1.6.6?
Permissions on running persistent volumes can be changed without affecting cluster operations using the Azure CLI or through the Azure web portal. A full procedure for both methods is available here: https://aka.ms/f5tslk
Azure Container Service rollout of 1.6.6 will begin immediately.
A CVE has been requested but not issued. A follow-up email will be sent once the CVE is used.
Thank You,
Brandon Philips
On-behalf of the Kubernetes Product Security Team