KubeVirt is a virtual machine management add-on for Kubernetes. In versions 0.59.0 and prior, if a malicious user has taken over a Kubernetes node where virt-handler (the KubeVirt node-daemon) is running, the virt-handler service account can be used to modify all node specs. This can be misused to lure-in system-level-privileged components which can, for instance, read all secrets on the cluster, or can exec into pods on other nodes. This way, a compromised node can be used to elevate privileges beyond the node until potentially having full privileged access to the whole cluster. The simplest way to exploit this, once a user could compromise a specific node, is to set with the virt-handler service account all other nodes to unschedulable and simply wait until system-critical components with high privileges appear on its node. No patches are available as of time of publication. As a workaround, gatekeeper users can add a webhook which will block the virt-handler
service account to modify the spec of a node.
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.
Name | Vendor | Start Version | End Version |
---|---|---|---|
Kubevirt | Kubevirt | * | 0.59.0 (including) |
Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are incorrectly applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.