Istio is an open platform to connect, manage, and secure microservices. In affected versions the Istio control plane, istiod, is vulnerable to a request processing error, allowing a malicious attacker that sends a specially crafted message which results in the control plane crashing when the validating webhook for a cluster is exposed publicly. This endpoint is served over TLS port 15017, but does not require any authentication from the attacker. For simple installations, Istiod is typically only reachable from within the cluster, limiting the blast radius. However, for some deployments, especially external istiod topologies, this port is exposed over the public internet. This issue has been patched in versions 1.13.2, 1.12.5 and 1.11.8. Users are advised to upgrade. Users unable to upgrade should disable access to a validating webhook that is exposed to the public internet or restrict the set of IP addresses that can query it to a set of known, trusted entities.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Istio | Istio | * | 1.11.8 (excluding) |
| Istio | Istio | 1.12.0 (including) | 1.12.5 (excluding) |
| Istio | Istio | 1.13.0 (including) | 1.13.2 (excluding) |
| OpenShift Service Mesh 2.0 | RedHat | servicemesh-0:2.0.9-3.el8 | * |
| OpenShift Service Mesh 2.1 | RedHat | servicemesh-0:2.1.2-4.el8 | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.