Permissions, Privileges, and Access Controls in k3s (Alpine package)

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU30806

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-11249

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to manipulate data.

The kubectl cp command allows copying files between containers and the user machine. To copy files from a container, Kubernetes runs tar inside the container to create a tar archive, 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. Kubernetes affected versions include versions prior to 1.13.9, versions prior to 1.14.5, versions prior to 1.15.2, and versions 1.1, 1.2, 1.4, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 1.10, 1.11, 1.12.

Mitigation

Install update from vendor's website.

Vulnerable software versions

k3s (Alpine package): 0.7.0-r0

External links

http://git.alpinelinux.org/aports/commit/?id=bd6c2b0202fd22c3155ba217e76bcb1164da3fa8

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.