1 files changed, 38 insertions, 0 deletions
diff --git a/punkctf/k8s_05.md b/punkctf/k8s_05.md
new file mode 100644
index 0000000..a3dcb2c
--- /dev/null
+++ b/punkctf/k8s_05.md
@@ -0,0 +1,38 @@
+
+Using `kubectl auth can-i --list` we find we can only create pods and look at their logs, but not exec into them.
+
+If we try the payload from the previous stage, we also find that there are now pod security policies in effect.
+It mentions we're using the baseline policy, which is described [here](https://kubernetes.io/docs/concepts/security/pod-security-standards/#baseline).
+
+Initially, I created a pod such as below to dump all the secrets being mounted, which included a token for the default service account for the namespace. I was hoping this would have more permissions, but it ended up a dead end.
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: get-sa-token
+spec:
+  containers:
+  - name: get-sa-token
+    image: busybox
+    imagePullPolicy: IfNotPresent
+    securityContext:
+      runAsUser: 0
+    command: [ "/bin/sh", "-c", "--" ]
+    args: [ "while true; do find /var/run/secrets -exec cat {} \\; ; sleep 30; done;" ]
+```
+
+Inspecting the running container though, we can see the IP of the host that runs it is `10.0.27.88`.
+
+We use the built in `pscan` function of busybox to port scan this IP - we do this because sometimes kubelets are misconfigured to allow anonymous access or similar, so we want to investigate. (the exact arg was `"while true; do pscan -P 10000 10.0.27.88; sleep 30; done;"`).
+
+After trying to access the kubelet and failing, the only other open port other than SSH is port 2375.
+Googling for it, this port usually indicates an unauthenticated docker socket.
+
+Unfortunately we don't have a docker CLI available to interact directly, so we need to use their [API](https://docs.docker.com/engine/api/v1.42/) directly, using wget.
+
+The container we create is equivalent to `docker run -v /:/host --user=0 busybox cat /host/etc/kubernetes/admin.conf`, and we then read the output through the logs endpoint. Unfortunately I lost my exact payloads for this :(.
+
+Once we have this, we list the secrets and print them out as before to get the flag.
+
+I found out later this wasn't actually the intended solution - turns out you have permission to edit the namespace so you can just remove the pod security policy and do the same as k8s 4.