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Symlink Attack in kubectl cp

Moderate severity GitHub Reviewed Published Feb 15, 2022 to the GitHub Advisory Database • Updated Sep 18, 2023

Package

gomod k8s.io/kubernetes (Go)

Affected versions

< 1.11.9
>= 1.12.0, < 1.12.7
>= 1.13.0, < 1.13.5

Patched versions

1.11.9
1.12.7
1.13.5

Description

The kubectl cp command allows copying files between containers and the user machine. To copy files from a container, Kubernetes creates a tar inside the container, copies it over the network, and kubectl unpacks it on the user’s machine. If the tar binary in the container is malicious, it could run any code and output unexpected, malicious results. An attacker could use this to write files to any path on the user’s machine when kubectl cp is called, limited only by the system permissions of the local user. The untar function can both create and follow symbolic links. The issue is resolved in kubectl v1.11.9, v1.12.7, v1.13.5, and v1.14.0.

References

Reviewed May 19, 2021
Published to the GitHub Advisory Database Feb 15, 2022
Last updated Sep 18, 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
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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:R/S:U/C:N/I:H/A:N

EPSS score

0.125%
(48th percentile)

Weaknesses

CVE ID

CVE-2019-1002101

GHSA ID

GHSA-34jx-wx69-9x8v

Source code

No known source code
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