Guides

Ensure that the cluster-admin role is only used where required (RBAC)

The RBAC role cluster-admin provides wide-ranging powers over the environment and should be used only where and when needed. Kubernetes provides a set of default roles where RBAC is used. Some of these roles such as cluster-admin provide wide-ranging privileges which should only be applied where absolutely necessary. Roles such as cluster-admin allow super-user access to perform any action on any resource. When used in a ClusterRoleBinding, it gives full control over every resource in the cluster and in all namespaces. When used in a RoleBinding, it gives full control over every resource in the rolebinding's namespace, including the namespace itself.

Suggest Edits

Risk Level: Informational
Cloud Entity: Kubernetes Role Binding
CloudGuard Rule ID: D9.K8S.IAM.32
Covered by Spectral: Yes
Category: Security, Identity, & Compliance

GSL LOGIC

KubernetesRoleBinding should not have role.name='cluster-admin'

REMEDIATION

Identify all clusterrolebindings to the cluster-admin role. Check if they are used and if they need this role or if they could use a role with fewer privileges. Where possible, first bind users to a lower privileged role and then remove the clusterrolebinding to the cluster-admin role :
kubectl delete clusterrolebinding [name]

References

  1. https://kubernetes.io/docs/admin/authorization/rbac/#user-facing-roles
  2. https://kubernetes.io/docs/tasks/administer-cluster/reconfigure-kubelet/ (EKS)

Kubernetes Role Binding

A role binding grants the permissions defined in a role to a user or set of users. It holds a list of subjects (users, groups, or service accounts), and a reference to the role being granted. A RoleBinding grants permissions within a specific namespace whereas a ClusterRoleBinding grants that access cluster-wide.

Compliance Frameworks

  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.0.1
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.1.0
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.2.0
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.3.0
  • CIS Google Kubernetes Engine (GKE) Benchmark v1.2.0
  • CIS Google Kubernetes Engine (GKE) Benchmark v1.4.0
  • CIS Kubernetes Benchmark v1.20
  • CIS Kubernetes Benchmark v1.23
  • CIS Kubernetes Benchmark v1.24
  • CIS Kubernetes Benchmark v1.4.0
  • CIS Kubernetes Benchmark v1.5.1
  • CIS Kubernetes Benchmark v1.6.1
  • CIS Microsoft Kubernetes Engine (AKS) Benchmark v1.1.0
  • CIS Microsoft Kubernetes Engine (AKS) Benchmark v1.3.0
  • CIS OpenShift Container Platform v4 Benchmark v1.1.0
  • CIS OpenShift Container Platform v4 Benchmark v1.4.0
  • Kubernetes NIST.SP.800-190
  • Kubernetes v.1.13 CloudGuard Best Practices
  • Kubernetes v.1.14 CloudGuard Best Practices
  • OpenShift Container Platform v3

Updated about 1 year ago