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Insufficiently restricted permissions on plugin directories

Moderate severity GitHub Reviewed Published Oct 4, 2021 in containerd/containerd • Updated Jan 31, 2024

Package

gomod github.com/containerd/containerd (Go)

Affected versions

< 1.4.11
>= 1.5.0, < 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:

References

@dmcgowan dmcgowan published to containerd/containerd Oct 4, 2021
Reviewed Oct 4, 2021
Published by the National Vulnerability Database Oct 4, 2021
Published to the GitHub Advisory Database Oct 4, 2021
Last updated Jan 31, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS score

0.045%
(16th percentile)

Weaknesses

CVE ID

CVE-2021-41103

GHSA ID

GHSA-c2h3-6mxw-7mvq

Source code

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