CVE-2021-41103
containerd is an open source container runtime with an emphasis on simplicity, robustness and portability. 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. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability. Users unable to update should limit access to the host to trusted users. Update directory permission on container bundles directories.
02 / AFFECTED SOFTWARE
Affected packages
60 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
containerd is an open source container runtime with an emphasis on simplicity, robustness and portability. 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. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability. Users unable to update should limit access to the host to trusted users. Update directory permission on container bundles directories.
### 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. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. ### Patches This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability. ### Workarounds Limit access to the host to trusted users. Update directory permission on container bundles directories. ### For more information If you have any questions or comments about this advisory: * Open an issue in [github.com/containerd/containerd](https://github.com/containerd/containerd/issues/new/choose) * Email us at [[email protected]](mailto:[email protected])
Insufficiently restricted permissions on plugin directories in github.com/containerd/containerd
05 / REFERENCES
Further evidence
- https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
- https://github.com/containerd/containerd/commit/5b46e404f6b9f661a205e28d59c982d3634148f8
- https://github.com/containerd/containerd/security/advisories/GHSA-c2h3-6mxw-7mvq
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB/
- https://security.gentoo.org/glsa/202401-31
- https://www.debian.org/security/2021/dsa-5002
- https://github.com/containerd/containerd
- https://github.com/containerd/containerd/releases/tag/v1.4.11
- https://github.com/containerd/containerd/releases/tag/v1.5.7
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB
- https://lists.fedoraproject.org/archives/list/[email protected]/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB
- https://lists.fedoraproject.org/archives/list/[email protected]/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB
- https://nvd.nist.gov/vuln/detail/CVE-2021-41103