<  Back to rules search

etcd server requires API servers present an SSL CA file when connecting

kubernetes

Classification:

compliance

Framework:

cis-kubernetes

Control:

1.2.32

Set up the kubernetes integration.

Description

etcd should be configured to make use of TLS encryption for client connections.

Rationale

etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should be protected by client authentication. This requires the API server to identify itself to the etcd server using a SSL Certificate Authority file.

Audit

Run the following command on the master node:

ps -ef | grep kube-apiserver

Verify that the --etcd-cafile argument exists and it is set as appropriate.

Remediation

Follow the Kubernetes documentation and set up the TLS connection between the apiserver and etcd. Then, edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and set the etcd certificate authority file parameter: --etcd-cafile=<path/to/ca-file>

Impact

TLS and client certificate authentication must be configured for etcd.

Default value

By default, --etcd-cafile is not set.

References

  1. https://kubernetes.io/docs/admin/kube-apiserver/
  2. https://coreos.com/etcd/docs/latest/op-guide/security.html

CIS controls

Version 6 14.2 Encrypt All Sensitive Information Over Less-trusted Networks - All communication of sensitive information over less-trusted networks should be encrypted. Whenever information flows over a network with a lower trust level, the information should be encrypted.

Version 7 14.4 Encrypt All Sensitive Information in Transit - Encrypt all sensitive information in transit.