Kubernetes Roles and ClusterRoles that grant permissions to bind RoleBindings or ClusterRoleBindings

Rule Details

Cortex AppSec Rule ID	APPSEC_K8S_157
Category - Subcategory	Kubernetes - Access Control
Provider	OTHER
Severity	MEDIUM
Framework	Helm, Kubernetes, Kustomize

Impact

Role or ClusterRoles that grant permissions to bind RoleBindings or ClusterRoleBindings should be minimized to reduce powerful identities in the cluster. Such Roles and ClusterRoles can attach existing permissions (Roles and ClusterRoles) to arbitrary identities. RoleBindings grant permissions over a namespace, while ClusterRoleBindings grant permissions over the entire cluster. Minimize such Roles and ClusterRoles to limit the number of powerful credentials that if compromised could escalate privileges and possibly take over the entire cluster.

How to Fix

Kind*: ClusterRole, Role

• Arguments: rules ClusterRoles and Roles that grant the "bind" verbs over "clusterrolebindings" or "rolebindings" in the "rbac.authorization.k8s.io" API group should be minimized. [source,go]

---

kind: ClusterRole apiVersion: rbac.authorization.k8s.io/v1 metadata: name: rules:

• apiGroups: ["rbac.authorization.k8s.io"] resources: ["roles", "clusterroles"] verbs: ["get", "list", "create", "update"] x- apiGroups: ["rbac.authorization.k8s.io"] x resources: ["clusterrolebindings"] x verbs: ["bind"]

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