RBAC Roles with Impersonate Permission

• Query id: 9f85c3f6-26fd-4007-938a-2e0cb0100980
• Query name: RBAC Roles with Impersonate Permission
• Platform: Kubernetes
• Severity: Medium
• Category: Access Control
• URL: Github

Description

Roles or ClusterRoles with the permission 'impersonate' allow subjects to assume the rights of other users, groups, or service accounts. In case of compromise, attackers may abuse this sudo-like functionality to achieve privilege escalation
Documentation

Code samples

Code samples with security vulnerabilities

Postitive test num. 1 - yaml file

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: impersonator-role
  namespace: default
rules:
- apiGroups: [""]
  resources: ["users", "groups", "serviceaccounts"]
  verbs: ["impersonate"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: rbac-impersonate-binding
subjects:
- kind: ServiceAccount
  name: impersonator-sa
  namespace: default
  apiGroup: ""
roleRef:
  kind: ClusterRole
  name: impersonator-role
  apiGroup: ""

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: impersonator-role-neg
  namespace: default
rules:
- apiGroups: [""]
  resources: ["users", "groups", "serviceaccounts"]
  verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: rbac-impersonate-binding
subjects:
- kind: ServiceAccount
  name: impersonator-sa-neg
  namespace: default
  apiGroup: ""
roleRef:
  kind: ClusterRole
  name: impersonator-role-neg
  apiGroup: ""