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Insufficiently restricted permissions on container root and plugin directories

Moderate
dmcgowan published GHSA-c2h3-6mxw-7mvq Oct 4, 2021

Package

gomod github.com/containerd/containerd (Go)

Affected versions

<1.4.11,<1.5.7

Patched versions

1.4.11,1.5.7

Description

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:

Severity

Moderate
5.9
/ 10

CVSS base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVE ID

CVE-2021-41103

Weaknesses

No CWEs