KubeVirt is a virtual machine management add-on for Kubernetes. In 1.5.0 and earlier, the permissions granted to the virt-handler service account, such as the ability to update VMI and patch nodes, could be abused to force a VMI migration to an attacker-controlled node. This vulnerability could otherwise allow an attacker to mark all nodes as unschedulable, potentially forcing the migration or creation of privileged pods onto a compromised node.

Affected: Go: kubevirt.io/kubevirt

### Summary

The permissions granted to the `virt-handler` service account, such as the ability to update VMI and patch nodes, could be abused to force a VMI migration to an attacker-controlled node.

### Details

Following the [GitHub security advisory published on March 23 2023](https://github.com/kubevirt/kubevirt/security/advisories/GHSA-cp96-jpmq-xrr2), a `ValidatingAdmissionPolicy` was introduced to impose restrictions on which sections of node resources the `virt-handler` service account can modify. For instance, the `spec` section of nodes has been made immutable, and modifications to the `labels` section are now limited to `kubevirt.io`-prefixed labels only. This vulnerability could otherwise allow an attacker to mark all nodes as unschedulable, potentially forcing the migration or creation of privileged pods onto a compromised node.

However, if a `virt-handler` service account is compromised, either through the pod itself or the underlying node, an attacker may still modify node labels, both on the compromised node and on other nodes within the cluster. Notably, `virt-handler` sets a specific `kubevirt.io` boolean label, `kubevirt.io/schedulable`, which indicates whether the node can host VMI workloads. An attacker could repeatedly patch other nodes by setting this label to `false`, thereby forcing all #acr("vmi") instances to be scheduled exclusively on the compromised node.

[Another finding](https://github.com/kubevirt/kubevirt/security/advisories/GHSA-ggp9-c9…

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