RBAC Roles with Exec Permission

• Query id: c589f42c-7924-4871-aee2-1cede9bc7cbc
• Query name: RBAC Roles with Exec Permission
• Platform: Kubernetes
• Severity: Medium
• Category: Access Control
• URL: Github

Description

Roles or ClusterRoles with RBAC permissions to run commands in containers via 'kubectl exec' could be abused by attackers to execute malicious code in case of compromise. To prevent this, the 'pods/exec' verb should not be used in production environments
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: my-namespace
  name: allow-exec
rules:
- apiGroups: [""]
  resources: ["pods", "pods/exec"]
  verbs: ["get", "list", "create"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: allow-exec
  namespace: my-namespace
subjects:
- kind: User
  name: bob
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: allow-exec
  apiGroup: ""

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: my-namespace
  name: allow-exec-neg
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "list", "create"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: allow-exec-neg
  namespace: my-namespace
subjects:
- kind: User
  name: bob
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: allow-exec-neg
  apiGroup: ""