Overview :
The Kubelet component in versions 1.15.0-1.15.9, 1.16.0-1.16.6, and 1.17.0-1.17.2 has been found to be vulnerable to a denial of service attack via the kubelet API, including the unauthenticated HTTP read-only API typically served on port 10255, and the authenticated HTTPS API typically served on port 10250.

CVE-2020-8551

 

wo security issues were discovered in Kubernetes that could lead to a recoverable denial of service.

CVE-2020-8551 affects the kubelet, and has been rated Medium (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

CVE-2020-8552 affects the API server, and has also been rated Medium (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Am I vulnerable?

If an attacker can make an authorized resource request to an unpatched API server (see below), then you may be vulnerable to CVE-2020-8552. If an attacker can make an authorized request to an unpatched kubelet, then you may be vulnerable to CVE-2020-8551.

Affected Versions

CVE-2020-8551 affects:
  • kubelet v1.17.0 – v1.17.2
  • kubelet v1.16.0 – v1.16.6
  • kubelet v1.15.0 – v1.15.10\
  • kubelets prior to v1.15.0 are unaffected
CVE-2020-8552 affects:
  • kube-apiserver v1.17.0 – v1.17.2
  • kube-apiserver v1.16.0 – v1.16.6
  • kube-apiserver < v1.15.10

How do I mitigate this vulnerability?

Prior to upgrading, these vulnerabilities can be mitigated by:

  • Preventing unauthenticated or unauthorized access to the affected components
  • The apiserver and kubelet should auto restart in the event of an OOM error

Fixed Versions

Both vulnerabilities are patched in kubernetes versions
  • v1.17.3
  • v1.16.7
  • v1.15.10

Additional Details

See the GitHub issues for more details:

CVE-2020-8551: https://github.com/kubernetes/kubernetes/issues/89377
CVE-2020-8552: https://github.com/kubernetes/kubernetes/issues/89378

References