A flaw was found in KubeVirts migration proxy. When spec.configuration.migrations.disableTLS is set to true on the KubeVirt custom resource, the target virt-handler binds a plain TCP listener on all interfaces (0.0.0.0/::) on a random port with no authentication, peer allow-list, or handshake token. This listener proxies directly into the target virt-launchers virtqemud control socket. An attacker with a running pod on the cluster network can connect to this listener and issue unfiltered libvirt RPC commands against another tenants virtual machine, including reading VM memory and configuration, modifying VM state via QMP, or destroying the VM. The bind address is unconditionally 0.0.0.0 — configuring a dedicated migration network via migrations.network only changes the advertised migration IP, not the listener bind address, so the port remains reachable on the pod network even when a dedicated migration network is configured. The API documentation describes disableTLS as removing the additional layer of live migration encryption without disclosing that it also removes all mutual authentication.
Weakness
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Kubevirt | Kubevirt | - (including) | - (including) |
| Openshift_virtualization | Redhat | 4 (including) | 4.22.0 (including) |
Potential Mitigations
- Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.
- Identify all potential communication channels, or other means of interaction with the software, to ensure that all channels are appropriately protected, including those channels that are assumed to be accessible only by authorized parties. Developers sometimes perform authentication at the primary channel, but open up a secondary channel that is assumed to be private. For example, a login mechanism may be listening on one network port, but after successful authentication, it may open up a second port where it waits for the connection, but avoids authentication because it assumes that only the authenticated party will connect to the port.
- In general, if the software or protocol allows a single session or user state to persist across multiple connections or channels, authentication and appropriate credential management need to be used throughout.
- Where possible, avoid implementing custom, “grow-your-own” authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment. These capabilities may avoid common weaknesses that are unique to authentication; support automatic auditing and tracking; and make it easier to provide a clear separation between authentication tasks and authorization tasks.
- In environments such as the World Wide Web, the line between authentication and authorization is sometimes blurred. If custom authentication routines are required instead of those provided by the server, then these routines must be applied to every single page, since these pages could be requested directly.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator [REF-45].
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/12.html
- https://cwe.mitre.org/data/definitions/166.html
- https://cwe.mitre.org/data/definitions/216.html
- https://cwe.mitre.org/data/definitions/36.html
- https://cwe.mitre.org/data/definitions/62.html