Knative Serving builds on Kubernetes to support deploying and serving of applications and functions as serverless containers. An attacker who controls a pod to a degree where they can control the responses from the /metrics endpoint can cause Denial-of-Service of the autoscaler from an unbound memory allocation bug. This is a DoS vulnerability, where a non-privileged Knative user can cause a DoS for the cluster. This issue has been patched in version 0.39.0.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Serving | Knative | * | 1.10.5 (excluding) |
| Serving | Knative | 1.11.0 (including) | 1.11.3 (excluding) |
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.