containerd is an open source container runtime. A bug was found in containerds CRI implementation where a user can exhaust memory on the host. In the CRI stream server, a goroutine is launched to handle terminal resize events if a TTY is requested. If the users process fails to launch due to, for example, a faulty command, the goroutine will be stuck waiting to send without a receiver, resulting in a memory leak. Kubernetes and crictl can both be configured to use containerds CRI implementation and the stream server is used for handling container IO. This bug has been fixed in containerd 1.6.12 and 1.5.16. Users should update to these versions to resolve the issue. Users unable to upgrade should ensure that only trusted images and commands are used and that only trusted users have permissions to execute commands in running containers.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Containerd | Linuxfoundation | * | 1.5.16 (excluding) |
| Containerd | Linuxfoundation | 1.6.0 (including) | 1.6.12 (excluding) |
| Containerd | Ubuntu | bionic | * |
| Containerd | Ubuntu | esm-apps/bionic | * |
| Containerd | Ubuntu | esm-apps/xenial | * |
| Containerd | Ubuntu | esm-infra/focal | * |
| Containerd | Ubuntu | focal | * |
| Containerd | Ubuntu | jammy | * |
| Containerd | Ubuntu | kinetic | * |
| Containerd | Ubuntu | trusty | * |
| Containerd | Ubuntu | upstream | * |
| Containerd | Ubuntu | xenial | * |
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.