containerd

## Impact containerd's CRI checkpoint import process contains a vulnerability where it fails to validate the image references specified within a checkpoint image's configuration. An attacker with permissions to create pods can use a crafted checkpoint image to force containerd to pull a malicious image and assign it an arbitrary local tag, thereby poisoning the node's local image cache.

### Impact A vulnerability in containerd allows a maliciously crafted image to cause a Denial of Service (DoS) condition. When creating a container from this image, memory exhaustion occurs, leading to an Out Of Memory (OOM) kill of the containerd process. This renders the container runtime API unavailable and can disrupt clients such as the Docker Engine or Kubernetes control-plane components.

### Impact A bug was found in containerd's CRI Attach implementation where a user can exhaust memory on the host due to goroutine leaks. Repetitive calls of CRI Attach (e.g., [`kubectl attach`](https://kubernetes.io/docs/reference/kubectl/generated/kubectl_attach/)) could increase the memory usage of containerd. ### Patches This bug has been fixed in the following containerd versions: * 2.2.0 * 2.1.5 * 2.0.7 * 1.7.29 Users should update to these versions to resolve the issue.

### Impact A bug was found in containerd where containers launched with a User set as a `UID:GID` larger than the maximum 32-bit signed integer can cause an overflow condition where the container ultimately runs as root (UID 0). This could cause unexpected behavior for environments that require containers to run as a non-root user.

## Impact Containers launched through containerd's CRI implementation (through Kubernetes, crictl, or any other pod/container client that uses the containerd CRI service) that share the same image may receive incorrect environment variables, including values that are defined for other containers. If the affected containers have different security contexts, this may allow sensitive information to be unintentionally shared.

# /sys/devices/virtual/powercap accessible by default to containers Intel's RAPL (Running Average Power Limit) feature, introduced by the Sandy Bridge microarchitecture, provides software insights into hardware energy consumption. To facilitate this, Intel introduced the powercap framework in Linux kernel 3.13, which reads values via relevant MSRs (model specific registers) and provides unprivileged userspace access via `sysfs`.

### Impact When importing an OCI image, there was no limit on the number of bytes read for certain files. A maliciously crafted image with a large file where a limit was not applied could cause a denial of service. ### Patches This bug has been fixed in containerd 1.6.18 and 1.5.18. Users should update to these versions to resolve the issue. ### Workarounds Ensure that only trusted images are used and that only trusted users have permissions to import images.

### Impact A bug was found in containerd where supplementary groups are not set up properly inside a container. If an attacker has direct access to a container and manipulates their supplementary group access, they may be able to use supplementary group access to bypass primary group restrictions in some cases, potentially gaining access to sensitive information or gaining the ability to execute code in that container.

### Impact A bug was found in containerd's 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 user's 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.

### Impact A bug was found in containerd's CRI implementation where programs inside a container can cause the containerd daemon to consume memory without bound during invocation of the `ExecSync` API. This can cause containerd to consume all available memory on the computer, denying service to other legitimate workloads.

## Impact If a container image manifest in the OCI Image format or Docker Image V2 Schema 2 format includes a URL for the location of a specific image layer (otherwise known as a “foreign layer”), the default containerd resolver will follow that URL to attempt to download it.

### Impact A bug was found in containerd where container root directories and some plugins had insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs.

## Impact A bug was found in containerd where pulling and extracting a specially-crafted container image can result in Unix file permission changes for existing files in the host’s filesystem. Changes to file permissions can deny access to the expected owner of the file, widen access to others, or set extended bits like setuid, setgid, and sticky. This bug does not directly allow files to be read, modified, or executed without an additional cooperating process.

## Impact Access controls for the shim’s API socket verified that the connecting process had an effective UID of 0, but did not otherwise restrict access to the abstract Unix domain socket. This would allow malicious containers running in the same network namespace as the shim, with an effective UID of 0 but otherwise reduced privileges, to cause new processes to be run with elevated privileges.