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Default inheritable capabilities for linux container should be empty

Moderate severity GitHub Reviewed Published May 11, 2022 in opencontainers/runc • Updated Mar 27, 2023

Package

gomod github.com/opencontainers/runc (Go)

Affected versions

< 1.1.2

Patched versions

1.1.2

Description

Impact

A bug was found in runc where runc exec --cap executed processes with non-empty inheritable Linux process capabilities, creating an atypical Linux environment and enabling programs with inheritable file capabilities to elevate those capabilities to the permitted set during execve(2).

This bug did not affect the container security sandbox as the inheritable set never contained more capabilities than were included in the container's bounding set.

Patches

This bug has been fixed in runc 1.1.2. Users should update to this version as soon as possible.

This fix changes runc exec --cap behavior such that the additional capabilities granted to the process being executed (as specified via --cap arguments) do not include inheritable capabilities.

In addition, runc spec is changed to not set any inheritable capabilities in the created example OCI spec (config.json) file.

Credits

The opencontainers project would like to thank Andrew G. Morgan for responsibly disclosing this issue in accordance with the opencontainers org security policy.

For more information

If you have any questions or comments about this advisory:

References

@cyphar cyphar published to opencontainers/runc May 11, 2022
Published by the National Vulnerability Database May 17, 2022
Published to the GitHub Advisory Database May 24, 2022
Reviewed May 24, 2022
Last updated Mar 27, 2023

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:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS score

0.045%
(15th percentile)

Weaknesses

CVE ID

CVE-2022-29162

GHSA ID

GHSA-f3fp-gc8g-vw66

Source code

github.com/opencontainers/runc

Credits

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