Benchmark on Kubernetes 1.27 with KubeOne 1.7.3

This guide helps you evaluate the security of a Kubernetes cluster created using KubeOne against each control in the CIS Kubernetes Benchmark.

This guide corresponds to the following versions of KubeOne, CIS Benchmarks, and Kubernetes:

Testing Methodology

Each control in the CIS Kubernetes Benchmark was evaluated. These are the possible results for each control:

🟢 Pass: The cluster passes the audit/control outlined in the benchmark.

🔵 Pass (Additional Configuration Required): The cluster passes the audit/control outlined in the benchmark with some extra configuration. The documentation is provided.

🔴 Fail: The audit/control will be fixed in a future KubeOne release.

Control Type: master

1.1. Control Plane Node Configuration Files

1.1.1: Ensure that the API server pod specification file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.2: Ensure that the API server pod specification file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.3: Ensure that the controller manager pod specification file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.4: Ensure that the controller manager pod specification file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.5: Ensure that the scheduler pod specification file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.6: Ensure that the scheduler pod specification file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.7: Ensure that the etcd pod specification file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.8: Ensure that the etcd pod specification file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.9: Ensure that the Container Network Interface file permissions are set to 600 or more restrictive (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

1.1.10: Ensure that the Container Network Interface file ownership is set to root:root (Manual)

Result: 🟢 Pass

1.1.11: Ensure that the etcd data directory permissions are set to 700 or more restrictive (Automated)

Result: 🟢 Pass

1.1.12: Ensure that the etcd data directory ownership is set to etcd:etcd (Automated)

Result: 🟢 Pass

Details: KubeOne runs etcd cluster as containers and there is not a etcd user and group on the system

1.1.13: Ensure that the admin.conf file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.14: Ensure that the admin.conf file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.15: Ensure that the scheduler.conf file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.16: Ensure that the scheduler.conf file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.17: Ensure that the controller-manager.conf file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

1.1.18: Ensure that the controller-manager.conf file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.19: Ensure that the Kubernetes PKI directory and file ownership is set to root:root (Automated)

Result: 🟢 Pass

1.1.20: Ensure that the Kubernetes PKI certificate file permissions are set to 600 or more restrictive (Manual)

Result: 🟢 Pass

1.1.21: Ensure that the Kubernetes PKI key file permissions are set to 600 (Manual)

Result: 🟢 Pass

1.2. API Server

1.2.1: Ensure that the –anonymous-auth argument is set to false (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

1.2.2: Ensure that the –token-auth-file parameter is not set (Automated)

Result: 🟢 Pass

1.2.3: Ensure that the –DenyServiceExternalIPs is set (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

1.2.4: Ensure that the –kubelet-client-certificate and –kubelet-client-key arguments are set as appropriate (Automated)

Result: 🟢 Pass

1.2.5: Ensure that the –kubelet-certificate-authority argument is set as appropriate (Automated)

Result: 🟢 Pass

1.2.6: Ensure that the –authorization-mode argument is not set to AlwaysAllow (Automated)

Result: 🟢 Pass

1.2.7: Ensure that the –authorization-mode argument includes Node (Automated)

Result: 🟢 Pass

1.2.8: Ensure that the –authorization-mode argument includes RBAC (Automated)

Result: 🟢 Pass

1.2.9: Ensure that the admission control plugin EventRateLimit is set (Manual)

Result: 🔴 Fail

Details: EventRateLimit admission control plugin in in Alpha state, please see here. Supporting Alpha features is under consideration.

1.2.10: Ensure that the admission control plugin AlwaysAdmit is not set (Automated)

Result: 🟢 Pass

1.2.11: Ensure that the admission control plugin AlwaysPullImages is set (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

1.2.12: Ensure that the admission control plugin SecurityContextDeny is set if PodSecurityPolicy is not used (Manual)

Result: 🔴 Fail

Details: SecurityContextDeny admission control plugin is deprecated as of Kubernetes 1.27, hence it is not enabled.

1.2.13: Ensure that the admission control plugin ServiceAccount is set (Automated)

Result: 🟢 Pass

1.2.14: Ensure that the admission control plugin NamespaceLifecycle is set (Automated)

Result: 🟢 Pass

1.2.15: Ensure that the admission control plugin NodeRestriction is set (Automated)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

1.2.16: Ensure that the –profiling argument is set to false (Automated)

Result: 🟢 Pass

1.2.17: Ensure that the –audit-log-path argument is set (Automated)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

1.2.18: Ensure that the –audit-log-maxage argument is set to 30 or as appropriate (Automated)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

1.2.19: Ensure that the –audit-log-maxbackup argument is set to 10 or as appropriate (Automated)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

1.2.20: Ensure that the –audit-log-maxsize argument is set to 100 or as appropriate (Automated)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

1.2.21: Ensure that the –request-timeout argument is set as appropriate (Manual)

Result: 🟢 Pass

Details: The timeout is set to 60 seconds by default. Setting this timeout limit to be too large can exhaust the API server resources making it prone to Denial-of-Service attack.

1.2.22: Ensure that the –service-account-lookup argument is set to true (Automated)

Result: 🟢 Pass

1.2.23: Ensure that the –service-account-key-file argument is set as appropriate (Automated)

Result: 🟢 Pass

1.2.24: Ensure that the –etcd-certfile and –etcd-keyfile arguments are set as appropriate (Automated)

Result: 🟢 Pass

1.2.25: Ensure that the –tls-cert-file and –tls-private-key-file arguments are set as appropriate (Automated)

Result: 🟢 Pass

1.2.26: Ensure that the –client-ca-file argument is set as appropriate (Automated)

Result: 🟢 Pass

1.2.27: Ensure that the –etcd-cafile argument is set as appropriate (Automated)

Result: 🟢 Pass

1.2.28: Ensure that the –encryption-provider-config argument is set as appropriate (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: Encryption configuration can be enabled as described here

1.2.29: Ensure that encryption providers are appropriately configured (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: Encryption configuration can be enabled as described here

1.2.30: Ensure that the API Server only makes use of Strong Cryptographic Ciphers (Manual)

Result: 🟢 Pass

1.3. Controller Manager

1.3.1: Ensure that the –terminated-pod-gc-threshold argument is set as appropriate (Manual)

Result: 🟢 Pass

1.3.2: Ensure that the –profiling argument is set to false (Automated)

Result: 🟢 Pass

1.3.3: Ensure that the –use-service-account-credentials argument is set to true (Automated)

Result: 🟢 Pass

1.3.4: Ensure that the –service-account-private-key-file argument is set as appropriate (Automated)

Result: 🟢 Pass

1.3.5: Ensure that the –root-ca-file argument is set as appropriate (Automated)

Result: 🟢 Pass

1.3.6: Ensure that the RotateKubeletServerCertificate argument is set to true (Automated)

Result: 🟢 Pass

1.3.7: Ensure that the –bind-address argument is set to 127.0.0.1 (Automated)

Result: 🟢 Pass

1.4. Scheduler

1.4.1: Ensure that the –profiling argument is set to false (Automated)

Result: 🟢 Pass

1.4.2: Ensure that the –bind-address argument is set to 127.0.0.1 (Automated)

Result: 🟢 Pass

Control Type: etcd

2. Etcd Node Configuration

2.1: Ensure that the –cert-file and –key-file arguments are set as appropriate (Automated)

Result: 🟢 Pass

2.2: Ensure that the –client-cert-auth argument is set to true (Automated)

Result: 🟢 Pass

2.3: Ensure that the –auto-tls argument is not set to true (Automated)

Result: 🟢 Pass

2.4: Ensure that the –peer-cert-file and –peer-key-file arguments are set as appropriate (Automated)

Result: 🟢 Pass

2.5: Ensure that the –peer-client-cert-auth argument is set to true (Automated)

Result: 🟢 Pass

2.6: Ensure that the –peer-auto-tls argument is not set to true (Automated)

Result: 🟢 Pass

2.7: Ensure that a unique Certificate Authority is used for etcd (Manual)

Result: 🟢 Pass

Control Type: controlplane

3.1. Authentication and Authorization

3.1.1: Client certificate authentication should not be used for users (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: KubeOne can be configured with OIDC authentication as described here

3.1.2: Service account token authentication should not be used for users (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: KubeOne can be configured with OIDC authentication as described here

3.1.3: Bootstrap token authentication should not be used for users (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: KubeOne can be configured with OIDC authentication as described here

3.2. Logging

3.2.1: Ensure that a minimal audit policy is created (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

3.2.2: Ensure that the audit policy covers key security concerns (Manual)

Result: 🔵 Pass (Additional Configuration Required)

Details: Audit logging is not enabled by default, it can be configured as described here

Control Type: node

4.1. Worker Node Configuration Files

4.1.1: Ensure that the kubelet service file permissions are set to 600 or more restrictive (Automated)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

4.1.2: Ensure that the kubelet service file ownership is set to root:root (Automated)

Result: 🟢 Pass

4.1.3: If proxy kubeconfig file exists ensure permissions are set to 600 or more restrictive (Manual)

Result: 🟢 Pass

Details: KubeOne does not contain /etc/kubernetes/proxy.conf file

4.1.4: If proxy kubeconfig file exists ensure ownership is set to root:root (Manual)

Result: 🟢 Pass

Details: KubeOne does not contain /etc/kubernetes/proxy.conf file

4.1.5: Ensure that the –kubeconfig kubelet.conf file permissions are set to 600 or more restrictive (Automated)

Result: 🟢 Pass

4.1.6: Ensure that the –kubeconfig kubelet.conf file ownership is set to root:root (Automated)

Result: 🟢 Pass

4.1.7: Ensure that the certificate authorities file permissions are set to 600 or more restrictive (Manual)

Result: 🟢 Pass

4.1.8: Ensure that the client certificate authorities file ownership is set to root:root (Manual)

Result: 🟢 Pass

4.1.9: If the kubelet config.yaml configuration file is being used validate permissions set to 600 or more restrictive (Automated)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

4.1.10: If the kubelet config.yaml configuration file is being used validate file ownership is set to root:root (Automated)

Result: 🟢 Pass

4.2. Kubelet

4.2.1: Ensure that the –anonymous-auth argument is set to false (Automated)

Result: 🟢 Pass

4.2.2: Ensure that the –authorization-mode argument is not set to AlwaysAllow (Automated)

Result: 🟢 Pass

4.2.3: Ensure that the –client-ca-file argument is set as appropriate (Automated)

Result: 🟢 Pass

4.2.4: Verify that the –read-only-port argument is set to 0 (Manual)

Result: 🟢 Pass

4.2.5: Ensure that the –streaming-connection-idle-timeout argument is not set to 0 (Manual)

Result: 🟢 Pass

4.2.6: Ensure that the –make-iptables-util-chains argument is set to true (Automated)

Result: 🟢 Pass

4.2.7: Ensure that the –hostname-override argument is not set (Manual)

Result: 🟢 Pass

4.2.8: Ensure that the eventRecordQPS argument is set to a level which ensures appropriate event capture (Manual)

Result: 🟢 Pass

4.2.9: Ensure that the –tls-cert-file and –tls-private-key-file arguments are set as appropriate (Manual)

Result: 🟢 Pass

Details: --tls-cert-file and --tls-private-key-file options are provided to Kubelet

4.2.10: Ensure that the –rotate-certificates argument is not set to false (Automated)

Result: 🟢 Pass

4.2.11: Verify that the RotateKubeletServerCertificate argument is set to true (Manual)

Result: 🟢 Pass

4.2.12: Ensure that the Kubelet only makes use of Strong Cryptographic Ciphers (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release

4.2.13: Ensure that a limit is set on pod PIDs (Manual)

Result: 🔴 Fail

The issue is under investigation to provide a fix in a future KubeOne release