Cis K8s V1120 1.3.3

---
name: cis-k8s-v1120-1.3.3
description: "Ensure that the --use-service-account-credentials argument is set to true (Automated)"
category: cis-k8s
version: "1.12.0"
author: cyberstrike-official
tags: [cis, kubernetes, control-plane, controller-manager]
cis_id: "1.3.3"
cis_benchmark: "CIS Kubernetes Benchmark v1.12.0"
tech_stack: [kubernetes]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# CIS Kubernetes Benchmark v1.12.0 - Control 1.3.3

## Profile Applicability

- **Level:** 1 - Master Node

## Description

Use individual service account credentials for each controller.

## Rationale

The controller manager creates a service account per controller in the `kube-system` namespace, generates a credential for it, and builds a dedicated API client with that service account credential for each controller loop to use. Setting the `--use-service-account-credentials` to `true` runs each control loop within the controller manager using a separate service account credential. When used in combination with RBAC, this ensures that the control loops run with the minimum permissions required to perform their intended tasks.

## Impact

Whatever authorizer is configured for the cluster, it must grant sufficient permissions to the service accounts to perform their intended tasks. When using the RBAC authorizer, those roles are created and bound to the appropriate service accounts in the `kube-system` namespace automatically with default roles and rolebindings that are auto-reconciled on startup.

If using other authorization methods (ABAC, Webhook, etc), the cluster deployer is responsible for granting appropriate permissions to the service accounts (the required permissions can be seen by inspecting the `controller-roles.yaml` and `controller-role-bindings.yaml` files for the RBAC roles.

## Audit Procedure

Run the following command on the Control Plane node:

```bash
ps -ef | grep kube-controller-manager
```

Verify that the `--use-service-account-credentials` argument is set to `true`.

## Remediation

Edit the Controller Manager pod specification file `/etc/kubernetes/manifests/kube-controller-manager.yaml` on the Control Plane node to set the below parameter.

```
--use-service-account-credentials=true
```

## Default Value

By default, `--use-service-account-credentials` is set to false.

## References

1. https://kubernetes.io/docs/admin/kube-controller-manager/
2. https://kubernetes.io/docs/admin/service-accounts-admin/
3. https://github.com/kubernetes/kubernetes/blob/release-1.6/plugin/pkg/auth/authorizer/rbac/bootstrappolicy/testdata/controller-roles.yaml
4. https://github.com/kubernetes/kubernetes/blob/release-1.6/plugin/pkg/auth/authorizer/rbac/bootstrappolicy/testdata/controller-role-bindings.yaml
5. https://kubernetes.io/docs/admin/authorization/rbac/#controller-roles

## CIS Controls

| Controls Version | Control                                           | IG 1 | IG 2 | IG 3 |
| ---------------- | ------------------------------------------------- | ---- | ---- | ---- |
| v8               | 5.2 Use Unique Passwords                          |      |      |      |
| v8               | 6.8 Define and Maintain Role-Based Access Control |      |      |      |
| v7               | 4.4 Use Unique Passwords                          |      |      |      |

## Profile

**Level 1 - Master Node** (Automated)