Auditing Kubernetes Cluster RBAC

When to Use

• When performing security assessments of Kubernetes clusters (EKS, GKE, AKS, or self-managed)
• When validating that RBAC policies enforce least privilege for users and service accounts
• When investigating potential lateral movement or privilege escalation within a Kubernetes cluster
• When compliance audits require documentation of access controls and permissions
• When onboarding new teams to a shared cluster and defining appropriate RBAC policies

Do not use for network policy auditing (use Cilium or Calico network policy tools), for container image scanning (use Trivy or Grype), or for runtime security monitoring (use Falco or Sysdig Secure).

Prerequisites

• kubectl configured with cluster-admin or equivalent read permissions to the target cluster
• rbac-tool installed (kubectl krew install rbac-tool or binary from GitHub)
• KubiScan installed (pip install kubiscan)
• Kubeaudit installed (brew install kubeaudit or from GitHub releases)
• Access to the cluster's audit logs for correlating RBAC findings with actual API access

Workflow

Step 1: Enumerate ClusterRoles and Roles with Dangerous Permissions

Identify roles with wildcard permissions, secret access, pod exec, or escalation capabilities.

# List all ClusterRoles with wildcard verb access
kubectl get clusterroles -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for role in data['items']:
    name = role['metadata']['name']
    for rule in role.get('rules', []):
        verbs = rule.get('verbs', [])
        resources = rule.get('resources', [])
        if '*' in verbs or '*' in resources:
            print(f'ClusterRole: {name}')
            print(f'  Verbs: {verbs}')
            print(f'  Resources: {resources}')
            print(f'  API Groups: {rule.get(\"apiGroups\", [])}')
            print()
"

# Find roles that can read secrets
kubectl get clusterroles -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for role in data['items']:
    name = role['metadata']['name']
    for rule in role.get('rules', []):
        resources = rule.get('resources', [])
        verbs = rule.get('verbs', [])
        if ('secrets' in resources or '*' in resources) and ('get' in verbs or 'list' in verbs or '*' in verbs):
            if not name.startswith('system:'):
                print(f'ClusterRole: {name} -> can access secrets (verbs: {verbs})')
"

# Find roles with pod/exec permissions (container escape risk)
kubectl get clusterroles -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for role in data['items']:
    name = role['metadata']['name']
    for rule in role.get('rules', []):
        resources = rule.get('resources', [])
        if 'pods/exec' in resources or 'pods/*' in resources:
            print(f'ClusterRole: {name} -> has pods/exec access')
"

Step 2: Audit ClusterRoleBindings and RoleBindings

Review bindings to identify who has elevated access and detect overly broad group assignments.

# List all ClusterRoleBindings with the subjects
kubectl get clusterrolebindings -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for binding in data['items']:
    name = binding['metadata']['name']
    role = binding['roleRef']['name']
    subjects = binding.get('subjects', [])
    for subject in subjects:
        kind = subject.get('kind', '')
        subj_name = subject.get('name', '')
        ns = subject.get('namespace', 'cluster-wide')
        print(f'{name} -> Role: {role} | {kind}: {subj_name} ({ns})')
" | sort

# Find bindings to cluster-admin
kubectl get clusterrolebindings -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for binding in data['items']:
    if binding['roleRef']['name'] == 'cluster-admin':
        print(f\"Binding: {binding['metadata']['name']}\")
        for subject in binding.get('subjects', []):
            print(f\"  {subject.get('kind')}: {subject.get('name')} (ns: {subject.get('namespace', 'N/A')})\")
"

# Find bindings granting access to all authenticated users
kubectl get clusterrolebindings -o json | python3 -c "
import json, sys
data = json.load(sys.stdin)
for binding in data['items']:
    for subject in binding.get('subjects', []):
        if subject.get('name') in ['system:authenticated', 'system:unauthenticated']:
            print(f\"WARNING: {binding['metadata']['name']} grants {binding['roleRef']['name']} to {subject['name']}\")
"

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