---
title: Hardening Guide v2.2
---

This document provides prescriptive guidance for hardening a production installation of Rancher v2.2.x. It outlines the configurations and controls required to address Kubernetes benchmark controls from the Center for Information Security (CIS).

> This hardening guide describes how to secure the nodes in your cluster, and it is recommended to follow this guide before installing Kubernetes.

This hardening guide is intended to be used with specific versions of the CIS Kubernetes Benchmark, Kubernetes, and Rancher:

Hardening Guide Version | Rancher Version | CIS Benchmark Version | Kubernetes Version
------------------------|----------------|-----------------------|------------------
Hardening Guide v2.2 | Rancher v2.2.x | Benchmark v1.4.1, 1.4.0 | Kubernetes 1.13

[Click here to download a PDF version of this document](https://releases.rancher.com/documents/security/2.2.x/Rancher_Hardening_Guide.pdf)

For more detail about evaluating a hardened cluster against the official CIS benchmark, refer to the [CIS Benchmark Rancher Self-Assessment Guide - Rancher v2.2.x](./self-assessment-guide-with-cis-v1.4-benchmark.md).

### Profile Definitions

The following profile definitions agree with the CIS benchmarks for Kubernetes.

A profile is a set of configurations that provide a certain amount of hardening. Generally, the more hardened an environment is, the more it affects performance.

#### Level 1

Items in this profile intend to:

- offer practical advice appropriate for the environment;
- deliver an obvious security benefit; and
- not alter the functionality or utility of the environment beyond an acceptable margin

#### Level 2

Items in this profile extend the “Level 1” profile and exhibit one or more of the following characteristics:

- are intended for use in environments or use cases where security is paramount
- act as a defense in depth measure
- may negatively impact the utility or performance of the technology

---

## 1.1 - Rancher HA Kubernetes cluster host configuration

### 1.1.1 - Configure default sysctl settings on all hosts

**Profile Applicability**

- Level 1

**Description**

Configure sysctl settings to match what the kubelet would set if allowed.

**Rationale**

We recommend that users launch the kubelet with the `--protect-kernel-defaults` option. The settings that the kubelet initially attempts to change can be set manually.

This supports the following control:

- 2.1.7 - Ensure that the `--protect-kernel-defaults` argument is set to true (Scored)

**Audit**

- Verify `vm.overcommit_memory = 1`

``` bash
sysctl vm.overcommit_memory
```

- Verify `kernel.panic = 10`

``` bash
sysctl kernel.panic
```

- Verify `kernel.panic_on_oops = 1`

``` bash
sysctl kernel.panic_on_oops
```

**Remediation**

- Set the following parameters in `/etc/sysctl.conf` on all nodes:

``` plain
vm.overcommit_memory=1
kernel.panic=10
kernel.panic_on_oops=1
```

- Run `sysctl -p` to enable the settings.

### 1.1.2 - Install the encryption provider configuration on all control plane nodes

**Profile Applicability**

- Level 1

**Description**

Create a Kubernetes encryption configuration file on each of the RKE nodes that will be provisioned with the `controlplane` role:

**NOTE:** The `--experimental-encryption-provider-config` flag in Kubernetes 1.13+ is actually `--encryption-provider-config`

**Rationale**

This configuration file will ensure that the Rancher RKE cluster encrypts secrets at rest, which Kubernetes does not do by default.

This supports the following controls:

- 1.1.34 - Ensure that the `--experimental-encryption-provider-config` argument is set as appropriate (Scored)
- 1.1.35 - Ensure that the encryption provider is set to `aescbc` (Scored)

**Audit**

On the control plane hosts for the Rancher HA cluster run:

``` bash
stat /opt/kubernetes/encryption.yaml
```

Ensure that:

- The file is present
- The file mode is `0600`
- The file owner is `root:root`
- The file contains:

``` yaml
apiVersion: apiserver.config.k8s.io/v1
kind: EncryptionConfiguration
resources:
  - resources:
    - secrets
    providers:
    - aescbc:
        keys:
        - name: key1
          secret: <32-byte base64 encoded string>
    - identity: {}
```

Where `aescbc` is the key type, and `secret` is populated with a 32-byte base64 encoded string.

**Remediation**

- Generate a key and an empty configuration file:

``` bash
head -c 32 /dev/urandom | base64 -i -
touch /opt/kubernetes/encryption.yaml
```

- Set the file ownership to `root:root` and the permissions to `0600`

``` bash
chown root:root /opt/kubernetes/encryption.yaml
chmod 0600 /opt/kubernetes/encryption.yaml
```

- Set the contents to:

``` yaml
apiVersion: v1
kind: EncryptionConfig
resources:
  - resources:
    - secrets
    providers:
    - aescbc:
        keys:
        - name: key1
          secret: <32-byte base64 encoded string>
    - identity: {}
```

Where `secret` is the 32-byte base64-encoded string generated in the first step.

**NOTE:**

Files that are placed in `/opt/kubernetes` need to be mounted in using the `extra_binds` functionality in RKE.

### 1.1.3 - Install the audit log configuration on all control plane nodes.

**Profile Applicability**

- Level 1

**Description**

Place the configuration file for Kubernetes audit logging on each of the control plane nodes in the cluster.

**Rationale**

The Kubernetes API has audit logging capability that is the best way to track actions in the cluster.

This supports the following controls:

- 1.1.15 - Ensure that the `--audit-log-path` argument is set as appropriate (Scored)
- 1.1.16 - Ensure that the `--audit-log-maxage` argument is as appropriate (Scored)
- 1.1.17 - Ensure that the `--audit-log-maxbackup` argument is set as appropriate (Scored)
- 1.1.18 - Ensure that the `--audit-log-maxsize` argument is set as appropriate (Scored)
- 1.1.37 - Ensure that the `AdvancedAuditing` argument is not set to false (Scored)

**Audit**

On each control plane node, run:

``` bash
stat /opt/kubernetes/audit.yaml
```

Ensure that:

- The file is present
- The file mode is `0600`
- The file owner is `root:root`
- The file contains:

``` yaml
apiVersion: audit.k8s.io/v1beta1
kind: Policy
rules:
- level: Metadata
```

**Remediation**

On nodes with the `controlplane` role:

- Generate an empty configuration file:

``` bash
touch /opt/kubernetes/audit.yaml
```

- Set the file ownership to `root:root` and the permissions to `0600`

``` bash
chown root:root /opt/kubernetes/audit.yaml
chmod 0600 /opt/kubernetes/audit.yaml
```

- Set the contents to:

``` yaml
apiVersion: audit.k8s.io/v1beta1
kind: Policy
rules:
- level: Metadata
```

**NOTE:**

Files that are placed in `/opt/kubernetes` need to be mounted in using the `extra_binds` functionality in RKE.

### 1.1.4 - Place Kubernetes event limit configuration on each control plane host

**Profile Applicability**

- Level 1

**Description**

Place the configuration file for Kubernetes event limit configuration on each of the control plane nodes in the cluster.

**Rationale**

Set up the `EventRateLimit` admission control plugin to prevent clients from overwhelming the API server. The settings below are intended as an initial value and may need to be adjusted for larger clusters.

This supports the following control:

- 1.1.36 - Ensure that the admission control plugin `EventRateLimit` is set (Scored)

**Audit**

On nodes with the `controlplane` role run:

``` bash
stat /opt/kubernetes/admission.yaml
stat /opt/kubernetes/event.yaml
```

For each file, ensure that:

- The file is present
- The file mode is `0600`
- The file owner is `root:root`

For `admission.yaml` ensure that the file contains:

``` yaml
apiVersion: apiserver.k8s.io/v1alpha1
kind: AdmissionConfiguration
plugins:
- name: EventRateLimit
  path: /opt/kubernetes/event.yaml
```

For `event.yaml` ensure that the file contains:

``` yaml
apiVersion: eventratelimit.admission.k8s.io/v1alpha1
kind: Configuration
limits:
- type: Server
  qps: 5000
  burst: 20000
```

**Remediation**

On nodes with the `controlplane` role:

- Generate an empty configuration file:

``` bash
touch /opt/kubernetes/admission.yaml
touch /opt/kubernetes/event.yaml
```

- Set the file ownership to `root:root` and the permissions to `0600`

``` bash
chown root:root /opt/kubernetes/admission.yaml
chown root:root /opt/kubernetes/event.yaml
chmod 0600 /opt/kubernetes/admission.yaml
chmod 0600 /opt/kubernetes/event.yaml
```

- For `admission.yaml` set the contents to:

``` yaml
apiVersion: apiserver.k8s.io/v1alpha1
kind: AdmissionConfiguration
plugins:
- name: EventRateLimit
  path: /opt/kubernetes/event.yaml
```

- For `event.yaml` set the contents to:

``` yaml
apiVersion: eventratelimit.admission.k8s.io/v1alpha1
kind: Configuration
limits:
- type: Server
  qps: 5000
  burst: 20000
```

**NOTE:**

Files that are placed in `/opt/kubernetes` need to be mounted in using the `extra_binds` functionality in RKE.

## 2.1 - Rancher HA Kubernetes Cluster Configuration via RKE

(See Appendix A. for full RKE `cluster.yml` example)

### 2.1.1 - Configure kubelet options

**Profile Applicability**

- Level 1

**Description**

Ensure Kubelet options are configured to match CIS controls.

**Rationale**

To pass the following controls in the CIS benchmark, ensure the appropriate flags are passed to the Kubelet.

- 2.1.1 -  Ensure that the `--anonymous-auth` argument is set to false (Scored)
- 2.1.2 - Ensure that the `--authorization-mode` argument is not set to `AlwaysAllow` (Scored)
- 2.1.6 - Ensure that the `--streaming-connection-idle-timeout` argument is not set to 0 (Scored)
- 2.1.7 - Ensure that the `--protect-kernel-defaults` argument is set to true (Scored)
- 2.1.8 - Ensure that the `--make-iptables-util-chains` argument is set to true (Scored)
- 2.1.10 - Ensure that the `--event-qps` argument is set to 0 (Scored)
- 2.1.13 - Ensure that the `RotateKubeletServerCertificate` argument is set to true (Scored)
- 2.1.14 - Ensure that the Kubelet only makes use of Strong Cryptographic Ciphers (Not Scored)

**Audit**

Inspect the Kubelet containers on all hosts and verify that they are running with the following options:

- `--streaming-connection-idle-timeout=<duration greater than 0>`
- `--authorization-mode=Webhook`
- `--protect-kernel-defaults=true`
- `--make-iptables-util-chains=true`
- `--event-qps=0`
- `--anonymous-auth=false`
- `--feature-gates="RotateKubeletServerCertificate=true"`
- `--tls-cipher-suites="TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"`

**Remediation**

- Add the following to the RKE `cluster.yml` kubelet section under `services`:

``` yaml
services:
  kubelet:
    extra_args:
      authorization-mode: "Webhook"
      streaming-connection-idle-timeout: "<duration>"
      protect-kernel-defaults: "true"
      make-iptables-util-chains: "true"
      event-qps: "0"
      anonymous-auth: "false"
      feature-gates: "RotateKubeletServerCertificate=true"
      tls-cipher-suites: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"
```

  Where `<duration>` is in a form like `1800s`.

- Reconfigure the cluster:

``` bash
rke up --config cluster.yml
```

### 2.1.2 - Configure kube-api options

**Profile Applicability**

- Level 1

**Description**

Ensure the RKE configuration is set to deploy the `kube-api` service with the options required for controls.

**NOTE:**

Enabling the `AlwaysPullImages` admission control plugin can cause degraded performance due to overhead of always pulling images.
Enabling the `DenyEscalatingExec` admission control plugin will prevent the 'Launch kubectl' functionality in the UI from working.

**Rationale**

To pass the following controls for the kube-api server ensure RKE configuration passes the appropriate options.

- 1.1.1 - Ensure that the `--anonymous-auth` argument is set to false (Scored)
- 1.1.8 - Ensure that the `--profiling argument` is set to false (Scored)
- 1.1.11 - Ensure that the admission control plugin `AlwaysPullImages` is set (Scored)
- 1.1.12 - Ensure that the admission control plugin `DenyEscalatingExec` is set (Scored)
- 1.1.14 - Ensure that the admission control plugin `NamespaceLifecycle` is set (Scored)
- 1.1.15 - Ensure that the `--audit-log-path` argument is set as appropriate (Scored)
- 1.1.16 - Ensure that the `--audit-log-maxage` argument is set as appropriate (Scored)
- 1.1.17 - Ensure that the `--audit-log-maxbackup` argument is set as appropriate (Scored)
- 1.1.18 - Ensure that the `--audit-log-maxsize` argument is set as appropriate (Scored)
- 1.1.23 - Ensure that the `--service-account-lookup` argument is set to true (Scored)
- 1.1.24 - Ensure that the admission control plugin `PodSecurityPolicy` is set (Scored)
- 1.1.30 Ensure that the API Server only makes use of Strong Cryptographic Ciphers (Not Scored)
- 1.1.34 - Ensure that the `--experimental-encryption-provider-config` argument is set as appropriate (Scored)
- 1.1.35 - Ensure that the encryption provider is set to `aescbc` (Scored)
- 1.1.36 - Ensure that the admission control plugin `EventRateLimit` is set (Scored)
- 1.1.37 - Ensure that the `AdvancedAuditing` argument is not set to `false` (Scored)

**Audit**

- On nodes with the `controlplane` role inspect the `kube-apiserver` containers:

  ``` bash
  docker inspect kube-apiserver
  ```

- Look for the following options in the command section of the output:

``` text
--anonymous-auth=false
--profiling=false
--service-account-lookup=true
--enable-admission-plugins= "ServiceAccount,NamespaceLifecycle,LimitRanger,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota,DefaultTolerationSeconds,AlwaysPullImages,DenyEscalatingExec,NodeRestriction,EventRateLimit,PodSecurityPolicy"
--encryption-provider-config=/opt/kubernetes/encryption.yaml
--admission-control-config-file=/opt/kubernetes/admission.yaml
--audit-log-path=/var/log/kube-audit/audit-log.json
--audit-log-maxage=5
--audit-log-maxbackup=5
--audit-log-maxsize=100
--audit-log-format=json
--audit-policy-file=/opt/kubernetes/audit.yaml
--tls-cipher-suites: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"
```

- In the `volume` section of the output ensure the bind mount is present:

``` text
/var/log/kube-audit:/var/log/kube-audit
```

**Remediation**

- In the RKE `cluster.yml` add the following directives to the `kube-api` section under `services`:

``` yaml
services:
  kube-api:
    pod_security_policy: true
    extra_args:
      anonymous-auth: "false"
      profiling: "false"
      service-account-lookup: "true"
      enable-admission-plugins: "ServiceAccount,NamespaceLifecycle,LimitRanger,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota,DefaultTolerationSeconds,AlwaysPullImages,DenyEscalatingExec,NodeRestriction,EventRateLimit,PodSecurityPolicy"
      encryption-provider-config: /opt/kubernetes/encryption.yaml
      admission-control-config-file: "/opt/kubernetes/admission.yaml"
      audit-log-path: "/var/log/kube-audit/audit-log.json"
      audit-log-maxage: "5"
      audit-log-maxbackup: "5"
      audit-log-maxsize: "100"
      audit-log-format: "json"
      audit-policy-file: /opt/kubernetes/audit.yaml
      tls-cipher-suites: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"
    extra_binds:
      - "/var/log/kube-audit:/var/log/kube-audit"
      - "/opt/kubernetes:/opt/kubernetes"
```

- Reconfigure the cluster:

``` bash
rke up --config cluster.yml
```

**NOTE:**

Files that are placed in `/opt/kubernetes` need to be mounted in using the `extra_binds` functionality in RKE.

### 2.1.3 - Configure scheduler options

**Profile Applicability**

- Level 1

**Description**

Set the appropriate options for the Kubernetes scheduling service.

**NOTE:** Setting `--address` to `127.0.0.1` will prevent Rancher cluster monitoring from scraping this endpoint.

**Rationale**

To address the following controls on the CIS benchmark, the command line options should be set on the Kubernetes scheduler.

- 1.2.1 - Ensure that the `--profiling` argument is set to `false` (Scored)
- 1.2.2 - Ensure that the `--address` argument is set to `127.0.0.1` (Scored)

**Audit**

- On nodes with the `controlplane` role: inspect the `kube-scheduler` containers:

``` bash
docker inspect kube-scheduler
```

- Verify the following options are set in the `command` section.

``` text
--profiling=false
--address=127.0.0.1
```

**Remediation**

- In the RKE `cluster.yml` file ensure the following options are set:

``` yaml
services:
  …
  scheduler:
    extra_args:
    profiling: "false"
    address: "127.0.0.1"
```

- Reconfigure the cluster:

``` bash
rke up --config cluster.yml
```

### 2.1.4 - Configure controller options

**Profile Applicability**

- Level 1

**Description**

Set the appropriate arguments on the Kubernetes controller manager.

**NOTE:** Setting `--address` to `127.0.0.1` will prevent Rancher cluster monitoring from scraping this endpoint.

**Rationale**

To address the following controls the options need to be passed to the Kubernetes controller manager.

- 1.3.1 - Ensure that the `--terminated-pod-gc-threshold` argument is set as appropriate (Scored)
- 1.3.2 - Ensure that the `--profiling` argument is set to false (Scored)
- 1.3.6 Ensure that the RotateKubeletServerCertificate argument is set to true (Scored)
- 1.3.7 - Ensure that the `--address` argument is set to 127.0.0.1 (Scored)

**Audit**

- On nodes with the `controlplane` role inspect the `kube-controller-manager` container:

``` bash
docker inspect kube-controller-manager
```

- Verify the following options are set in the `command` section:

``` text
--terminated-pod-gc-threshold=1000
--profiling=false
--address=127.0.0.1
--feature-gates="RotateKubeletServerCertificate=true"
```

**Remediation**

- In the RKE `cluster.yml` file ensure the following options are set:

``` yaml
services:
  kube-controller:
    extra_args:
      profiling: "false"
      address: "127.0.0.1"
      terminated-pod-gc-threshold: "1000"
      feature-gates: "RotateKubeletServerCertificate=true"
```

- Reconfigure the cluster:

``` bash
rke up --config cluster.yml
```

### 2.1.5 - Configure addons and PSPs

**Profile Applicability**

- Level 1

**Description**

Configure a restrictive pod security policy (PSP) as the default and create role bindings for system level services to use the less restrictive default PSP.

**Rationale**

To address the following controls, a restrictive default PSP needs to be applied as the default. Role bindings need to be in place to allow system services to still function.

- 1.7.1 - Do not admit privileged containers (Not Scored)
- 1.7.2 - Do not admit containers wishing to share the host process ID namespace (Not Scored)
- 1.7.3 - Do not admit containers wishing to share the host IPC namespace (Not Scored)
- 1.7.4 - Do not admit containers wishing to share the host network namespace (Not Scored)
- 1.7.5 - Do not admit containers with `allowPrivilegeEscalation` (Not Scored)
- 1.7.6 - Do not admit root containers (Not Scored)
- 1.7.7 - Do not admit containers with dangerous capabilities (Not Scored)

**Audit**

- Verify that the `cattle-system` namespace exists:

``` bash
kubectl get ns |grep cattle
```

- Verify that the roles exist:

``` bash
kubectl get role default-psp-role -n ingress-nginx
kubectl get role default-psp-role -n cattle-system
kubectl get clusterrole psp:restricted
```

- Verify the bindings are set correctly:

``` bash
kubectl get rolebinding -n ingress-nginx default-psp-rolebinding
kubectl get rolebinding -n cattle-system default-psp-rolebinding
kubectl get clusterrolebinding psp:restricted
```

- Verify the restricted PSP is present.

``` bash
kubectl get psp restricted
```

**Remediation**

- In the RKE `cluster.yml` file ensure the following options are set:

``` yaml
addons: |
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: default-psp-role
    namespace: ingress-nginx
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - default-psp
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: default-psp-rolebinding
    namespace: ingress-nginx
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: default-psp-role
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
  ---
  apiVersion: v1
  kind: Namespace
  metadata:
    name: cattle-system
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: default-psp-role
    namespace: cattle-system
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - default-psp
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: default-psp-rolebinding
    namespace: cattle-system
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: default-psp-role
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
  ---
  apiVersion: extensions/v1beta1
  kind: PodSecurityPolicy
  metadata:
    name: restricted
  spec:
    requiredDropCapabilities:
    - NET_RAW
    privileged: false
    allowPrivilegeEscalation: false
    defaultAllowPrivilegeEscalation: false
    fsGroup:
      rule: RunAsAny
    runAsUser:
      rule: MustRunAsNonRoot
    seLinux:
      rule: RunAsAny
    supplementalGroups:
      rule: RunAsAny
    volumes:
    - emptyDir
    - secret
    - persistentVolumeClaim
    - downwardAPI
    - configMap
    - projected
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: ClusterRole
  metadata:
    name: psp:restricted
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - restricted
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: ClusterRoleBinding
  metadata:
    name: psp:restricted
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: ClusterRole
    name: psp:restricted
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
```

- Reconfigure the cluster:

``` bash
rke up --config cluster.yml
```

## 3.1 - Rancher Management Control Plane Installation

### 3.1.1 - Disable the local cluster option

**Profile Applicability**

- Level 2

**Description**

When deploying Rancher, disable the local cluster option on the Rancher Server.

**NOTE:** This requires Rancher v2.1.2 or above.

**Rationale**

Having access to the local cluster from the Rancher UI is convenient for troubleshooting and debugging; however, if the local cluster is enabled in the Rancher UI, a user has access to all elements of the system, including the Rancher management server itself. Disabling the local cluster is a defense in depth measure and removes the possible attack vector from the Rancher UI and API.

**Audit**

- Verify the Rancher deployment has the `--add-local=false` option set.

``` bash
kubectl get deployment rancher -n cattle-system -o yaml |grep 'add-local'
```

- In the Rancher UI go to _Clusters_ in the _Global_ view and verify that no `local` cluster is present.

**Remediation**

- While upgrading or installing Rancher 2.2.x, provide the following flag:

``` text
--set addLocal="false"
```

### 3.1.2 - Enable Rancher Audit logging

**Profile Applicability**

- Level 1

**Description**

Enable Rancher’s built-in audit logging capability.

**Rationale**

Tracking down what actions were performed by users in Rancher can provide insight during post mortems, and if monitored proactively can be used to quickly detect malicious actions.

**Audit**

- Verify that the audit log parameters were passed into the Rancher deployment.

```
kubectl get deployment rancher -n cattle-system -o yaml | grep auditLog
```

- Verify that the log is going to the appropriate destination, as set by
`auditLog.destination`

  - `sidecar`:

    1. List pods:

        ``` bash
        kubectl get pods -n cattle-system
        ```

    2. Tail logs:

        ``` bash
        kubectl logs <pod> -n cattle-system -c rancher-audit-log
        ```

  - `hostPath`

    1. On the worker nodes running the Rancher pods, verify that the log files are being written to the destination indicated in `auditlog.hostPath`.

**Remediation**

Upgrade the Rancher server installation using Helm, and configure the audit log settings. The instructions for doing so can be found in the reference section below.

#### Reference

- <https://rancher.com/docs/rancher/v2.0-v2.4/en/installation/resources/chart-options/>

## 3.2 - Rancher Management Control Plane Authentication

### 3.2.1 - Change the local administrator password from the default value

**Profile Applicability**

- Level 1

**Description**

The local administrator password should be changed from the default.

**Rationale**

The default administrator password is common across all Rancher installations and should be changed immediately upon startup.

**Audit**

Attempt to login into the UI with the following credentials:
  - Username: admin
  - Password: admin

The login attempt must not succeed.

**Remediation**

Change the password from `admin` to a password that meets the recommended password standards for your organization.

### 3.2.2 - Configure an Identity Provider for Authentication

**Profile Applicability**

- Level 1

**Description**

When running Rancher in a production environment, configure an identity provider for authentication.

**Rationale**

Rancher supports several authentication backends that are common in enterprises. It is recommended to tie Rancher into an external authentication system to simplify user and group access in the Rancher cluster. Doing so assures that access control follows the organization's change management process for user accounts.

**Audit**

- In the Rancher UI, select _Global_
- Select _Security_
- Select _Authentication_
- Ensure the authentication provider for your environment is active and configured correctly

**Remediation**

Configure the appropriate authentication provider for your Rancher installation according to the documentation found at the link in the reference section below.

#### Reference

- <https://rancher.com/docs/rancher/v2.0-v2.4/en/admin-settings/authentication/>

## 3.3 - Rancher Management Control Plane RBAC

### 3.3.1 - Ensure that administrator privileges are only granted to those who require them

**Profile Applicability**

- Level 1

**Description**

Restrict administrator access to only those responsible for managing and operating the Rancher server.

**Rationale**

The `admin`  privilege level gives the user the highest level of access to the Rancher server and all attached clusters. This privilege should only be granted to a few people who are responsible for the availability and support of Rancher and the clusters that it manages.

**Audit**

The following script uses the Rancher API to show users with administrator privileges:

``` bash
#!/bin/bash
for i in $(curl -sk -u 'token-<id>:<secret>' https://<RANCHER_URL>/v3/users|jq -r .data[].links.globalRoleBindings); do

curl -sk -u 'token-<id>:<secret>' $i| jq '.data[] | "\(.userId) \(.globalRoleId)"'

done

```

The `admin` role should only be assigned to users that require administrative privileges. Any role that is not `admin` or `user` should be audited in the RBAC section of the UI to ensure that the privileges adhere to policies for global access.

The Rancher server permits customization of the default global permissions. We recommend that auditors also review the policies of any custom global roles.

**Remediation**

Remove the `admin` role from any user that does not require administrative privileges.

## 3.4 - Rancher Management Control Plane Configuration

### 3.4.1 - Ensure only approved node drivers are active

**Profile Applicability**

- Level 1

**Description**

Ensure that node drivers that are not needed or approved are not active in the Rancher console.

**Rationale**

Node drivers are used to provision compute nodes in various cloud providers and local IaaS infrastructure. For convenience, popular cloud providers are enabled by default. If the organization does not intend to use these or does not allow users to provision resources in certain providers, the drivers should be disabled. This will prevent users from using Rancher resources to provision the nodes.

**Audit**

- In the Rancher UI select _Global_
- Select _Node Drivers_
- Review the list of node drivers that are in an _Active_ state.

**Remediation**

If a disallowed node driver is active, visit the _Node Drivers_ page under _Global_ and disable it.

---

## Appendix A - Complete RKE `cluster.yml` Example

``` yaml
nodes:
- address: 18.191.190.205
  internal_address: 172.31.24.213
  user: ubuntu
  role: [ "controlplane", "etcd", "worker" ]
- address: 18.191.190.203
  internal_address: 172.31.24.203
  user: ubuntu
  role: [ "controlplane", "etcd", "worker" ]
- address: 18.191.190.10
  internal_address: 172.31.24.244
  user: ubuntu
  role: [ "controlplane", "etcd", "worker" ]

services:
  kubelet:
    extra_args:
      streaming-connection-idle-timeout: "1800s"
      authorization-mode: "Webhook"
      protect-kernel-defaults: "true"
      make-iptables-util-chains: "true"
      event-qps: "0"
      anonymous-auth: "false"
      feature-gates: "RotateKubeletServerCertificate=true"
      tls-cipher-suites: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"
  kube-api:
    pod_security_policy: true
    extra_args:
      anonymous-auth: "false"
      profiling: "false"
      service-account-lookup: "true"
      enable-admission-plugins: "ServiceAccount,NamespaceLifecycle,LimitRanger,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota,DefaultTolerationSeconds,AlwaysPullImages,DenyEscalatingExec,NodeRestriction,EventRateLimit,PodSecurityPolicy"
      encryption-provider-config: /opt/kubernetes/encryption.yaml
      admission-control-config-file: "/opt/kubernetes/admission.yaml"
      audit-log-path: "/var/log/kube-audit/audit-log.json"
      audit-log-maxage: "5"
      audit-log-maxbackup: "5"
      audit-log-maxsize: "100"
      audit-log-format: "json"
      audit-policy-file: /opt/kubernetes/audit.yaml
      tls-cipher-suites: "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_256_GCM_SHA384,TLS_RSA_WITH_AES_128_GCM_SHA256"
    extra_binds:
      - "/var/log/kube-audit:/var/log/kube-audit"
      - "/opt/kubernetes:/opt/kubernetes"
  scheduler:
    extra_args:
      profiling: "false"
      address: "127.0.0.1"
  kube-controller:
    extra_args:
      profiling: "false"
      address: "127.0.0.1"
      terminated-pod-gc-threshold: "1000"
      feature-gates: "RotateKubeletServerCertificate=true"
addons: |
  apiVersion: v1
  kind: Namespace
  metadata:
    name: ingress-nginx
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: default-psp-role
    namespace: ingress-nginx
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - default-psp
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: default-psp-rolebinding
    namespace: ingress-nginx
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: default-psp-role
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
  ---
  apiVersion: v1
  kind: Namespace
  metadata:
    name: cattle-system
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: default-psp-role
    namespace: cattle-system
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - default-psp
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: RoleBinding
  metadata:
    name: default-psp-rolebinding
    namespace: cattle-system
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: Role
    name: default-psp-role
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
  ---
  apiVersion: extensions/v1beta1
  kind: PodSecurityPolicy
  metadata:
    name: restricted
  spec:
    requiredDropCapabilities:
    - NET_RAW
    privileged: false
    allowPrivilegeEscalation: false
    defaultAllowPrivilegeEscalation: false
    fsGroup:
      rule: RunAsAny
    runAsUser:
      rule: MustRunAsNonRoot
    seLinux:
      rule: RunAsAny
    supplementalGroups:
      rule: RunAsAny
    volumes:
    - emptyDir
    - secret
    - persistentVolumeClaim
    - downwardAPI
    - configMap
    - projected
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: ClusterRole
  metadata:
    name: psp:restricted
  rules:
  - apiGroups:
    - extensions
    resourceNames:
    - restricted
    resources:
    - podsecuritypolicies
    verbs:
    - use
  ---
  apiVersion: rbac.authorization.k8s.io/v1
  kind: ClusterRoleBinding
  metadata:
    name: psp:restricted
  roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: ClusterRole
    name: psp:restricted
  subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:authenticated
```
