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, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
| 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/xenial | * |
| Containerd | Ubuntu | focal | * |
| Containerd | Ubuntu | jammy | * |
| Containerd | Ubuntu | kinetic | * |
| Containerd | Ubuntu | trusty | * |
| Containerd | Ubuntu | upstream | * |
| Containerd | Ubuntu | xenial | * |
Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:
Resource exhaustion problems are often result due to an incorrect implementation of the following situations:
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.