Resource exhaustion in Kubernetes

1) Resource exhaustion

EUVDB-ID: #VU34052

Risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8557

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

The vulnerability allows a local authenticated user to perform a denial of service (DoS) attack.

The Kubernetes kubelet component in versions 1.1-1.16.12, 1.17.0-1.17.8 and 1.18.0-1.18.5 do not account for disk usage by a pod which writes to its own /etc/hosts file. The /etc/hosts file mounted in a pod by kubelet is not included by the kubelet eviction manager when calculating ephemeral storage usage by a pod. If a pod writes a large amount of data to the /etc/hosts file, it could fill the storage space of the node and cause the node to fail.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Kubernetes: 1.18.0 - 1.18.5

External links

http://github.com/kubernetes/kubernetes/issues/93032
http://groups.google.com/g/kubernetes-security-announce/c/cB_JUsYEKyY/m/vVSO61AhBwAJ

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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