Withdrawn by the publisher.

The imgcrypt library provides API exensions for containerd to support encrypted container images and implements the ctd-decoder command line tool for use by containerd to decrypt encrypted container images. The imgcrypt function `CheckAuthorization` is supposed to check whether the current used is authorized to access an encrypted image and prevent the user from running an image that another user previously decrypted on the same system. In versions prior to 1.1.4, a failure occurs when an image with a ManifestList is used and the architecture of the local host is not the first one in the ManifestList. Only the first architecture in the list was tested, which may not have its layers available locally since it could not be run on the host architecture. Therefore, the verdict on unavailable layers was that the image could be run anticipating that image run failure would occur later due to the layers not being available. However, this verdict to allow the image to run enabled other architectures in the ManifestList to run an image without providing keys if that image had previously been decrypted. A patch has been applied to imgcrypt 1.1.4. Workarounds may include usage of different namespaces for each remote user.

Affected: Go: github.com/containerd/imgcrypt

Imgcrypt implements a function `CheckAuthorization()` that is supposed to check whether a user is authorized to access an encrypted image given the keys that the user has provided on the command line that would enable decryption of the image. The check is to prevent that a user can start a container from an image that has previously been decrypted by another user on the same system and therefore a decrypted version of the image layers may be already available in the cache locally.

The failure occurs when an image with a ManifestList is used and the architecture of the local host is not the first one in the ManifestList. In the version prior to the fix, only the first architecture in the list was tested, which may not have its layers available locally (were not pulled) since it cannot be run on the host architecture. Therefore, the verdict on unavailable layers was that the image could be run anticipating that image run failure would occur later due to the layers not being available. However, this verdict to allow the image to run lead to other architectures in the ManifestList be able to run an image without providing keys if that image had previously been decrypted. The fixed version now skips over irrelevant architectures and tests the Manifest of the local architecture, if available.

Known projects that use the `CheckAuthorization()` of imgcrypt is for example the ctr-enc client tool provided by imgcrypt. In this implementation, the call to `CheckAuthorization()` is use…

cached-path-relative: Prototype Pollution via the cache variable nanoid: Information disclosure via valueOf() function opencontainers: OCI manifest and index parsing confusion golang.org/x/crypto: empty plaintext packet causes panic nodejs-shelljs: improper privilege management follow-redirects: Exposure of Private Personal Information to an Unauthorized Actor node-fetch: exposure of sensitive information to an unauthorized actor follow-redirects: Exposure of Sensitive Information via Authorization Header leak openssl: Infinite loop in BN_mod_sqrt() reachable when parsing certificates nats-server: misusing the "dynamically provisioned sandbox accounts" feature authenticated user can obtain the privileges of the System account imgcrypt: Unauthorized access to encryted container image on a shared system due to missing check in CheckAuthorization() code path golang: crash in a golang.org/x/crypto/ssh server

Affected: Ubuntu:Pro:16.04:LTS: containerd, Ubuntu:18.04:LTS: containerd, Ubuntu:20.04:LTS: containerd, Ubuntu:22.04:LTS: containerd

The imgcrypt library provides API exensions for containerd to support encrypted container images and implements the ctd-decoder command line tool for use by containerd to decrypt encrypted container images. The imgcrypt function `CheckAuthorization` is supposed to check whether the current used is authorized to access an encrypted image and prevent the user from running an image that another user previously decrypted on the same system. In versions prior to 1.1.4, a failure occurs when an image with a ManifestList is used and the architecture of the local host is not the first one in the ManifestList. Only the first architecture in the list was tested, which may not have its layers available locally since it could not be run on the host architecture. Therefore, the verdict on unavailable layers was that the image could be run anticipating that image run failure would occur later due to the layers not being available. However, this verdict to allow the image to run enabled other architectures in the ManifestList to run an image without providing keys if that image had previously been decrypted. A patch has been applied to imgcrypt 1.1.4. Workarounds may include usage of different namespaces for each remote user.