2023 Easy Success Linux Foundation CKS Exam in First Try [Q18-Q42]

NO.18 SIMULATION
Enable audit logs in the cluster, To Do so, enable the log backend, and ensure that
1. logs are stored at /var/log/kubernetes/kubernetes-logs.txt.
2. Log files are retained for 5 days.
3. at maximum, a number of 10 old audit logs files are retained.
Edit and extend the basic policy to log:
1. Cronjobs changes at RequestResponse
2. Log the request body of deployments changes in the namespace kube-system.
3. Log all other resources in core and extensions at the Request level.
4. Don’t log watch requests by the “system:kube-proxy” on endpoints or

NO.19 Fix all issues via configuration and restart the affected components to ensure the new setting takes effect.
Fix all of the following violations that were found against the API server:- a. Ensure that the RotateKubeletServerCertificate argument is set to true.
b. Ensure that the admission control plugin PodSecurityPolicy is set.
c. Ensure that the –kubelet-certificate-authority argument is set as appropriate.
Fix all of the following violations that were found against the Kubelet:- a. Ensure the –anonymous-auth argument is set to false.
b. Ensure that the –authorization-mode argument is set to Webhook.
Fix all of the following violations that were found against the ETCD:-
a. Ensure that the –auto-tls argument is not set to true
b. Ensure that the –peer-auto-tls argument is not set to true
Hint: Take the use of Tool Kube-Bench

NO.20 You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context dev A default-deny NetworkPolicy avoid to accidentally expose a Pod in a namespace that doesn’t have any other NetworkPolicy defined.
Task: Create a new default-deny NetworkPolicy named deny-network in the namespace test for all traffic of type Ingress + Egress The new NetworkPolicy must deny all Ingress + Egress traffic in the namespace test.
Apply the newly created default-deny NetworkPolicy to all Pods running in namespace test.
You can find a skeleton manifests file at /home/cert_masters/network-policy.yaml

NO.21 SIMULATION
Secrets stored in the etcd is not secure at rest, you can use the etcdctl command utility to find the secret value for e.g:- ETCDCTL_API=3 etcdctl get /registry/secrets/default/cks-secret –cacert=”ca.crt” –cert=”server.crt” –key=”server.key” Output

Using the Encryption Configuration, Create the manifest, which secures the resource secrets using the provider AES-CBC and identity, to encrypt the secret-data at rest and ensure all secrets are encrypted with the new configuration.

NO.22 SIMULATION
use the Trivy to scan the following images,
1. amazonlinux:1
2. k8s.gcr.io/kube-controller-manager:v1.18.6
Look for images with HIGH or CRITICAL severity vulnerabilities and store the output of the same in /opt/trivy-vulnerable.txt

NO.23 SIMULATION
Create a User named john, create the CSR Request, fetch the certificate of the user after approving it.
Create a Role name john-role to list secrets, pods in namespace john
Finally, Create a RoleBinding named john-role-binding to attach the newly created role john-role to the user john in the namespace john. To Verify: Use the kubectl auth CLI command to verify the permissions.

NO.24 a. Retrieve the content of the existing secret named default-token-xxxxx in the testing namespace.
Store the value of the token in the token.txt
b. Create a new secret named test-db-secret in the DB namespace with the following content:
username: mysql
password: password@123
Create the Pod name test-db-pod of image nginx in the namespace db that can access test-db-secret via a volume at path /etc/mysql-credentials

NO.25 Analyze and edit the given Dockerfile
FROM ubuntu:latest
RUN apt-get update -y
RUN apt-install nginx -y
COPY entrypoint.sh /
ENTRYPOINT [“/entrypoint.sh”]
USER ROOT
Fixing two instructions present in the file being prominent security best practice issues Analyze and edit the deployment manifest file apiVersion: v1 kind: Pod metadata:
name: security-context-demo-2
spec:
securityContext:
runAsUser: 1000
containers:
– name: sec-ctx-demo-2
image: gcr.io/google-samples/node-hello:1.0
securityContext:
runAsUser: 0
privileged: True
allowPrivilegeEscalation: false
Fixing two fields present in the file being prominent security best practice issues Don’t add or remove configuration settings; only modify the existing configuration settings Whenever you need an unprivileged user for any of the tasks, use user test-user with the user id 5487

NO.26 Context
This cluster uses containerd as CRI runtime.
Containerd’s default runtime handler is runc. Containerd has been prepared to support an additional runtime handler, runsc (gVisor).
Task
Create a RuntimeClass named sandboxed using the prepared runtime handler named runsc.
Update all Pods in the namespace server to run on gVisor.

NO.27 Using the runtime detection tool Falco, Analyse the container behavior for at least 20 seconds, using filters that detect newly spawning and executing processes in a single container of Nginx.
store the incident file art /opt/falco-incident.txt, containing the detected incidents. one per line, in the format
[timestamp],[uid],[processName]

NO.28 Given an existing Pod named test-web-pod running in the namespace test-system Edit the existing Role bound to the Pod’s Service Account named sa-backend to only allow performing get operations on endpoints.
Create a new Role named test-system-role-2 in the namespace test-system, which can perform patch operations, on resources of type statefulsets.

NO.29 Context
A Role bound to a Pod’s ServiceAccount grants overly permissive permissions. Complete the following tasks to reduce the set of permissions.
Task
Given an existing Pod named web-pod running in the namespace security.
Edit the existing Role bound to the Pod’s ServiceAccount sa-dev-1 to only allow performing watch operations, only on resources of type services.
Create a new Role named role-2 in the namespace security, which only allows performing update operations, only on resources of type namespaces.
Create a new RoleBinding named role-2-binding binding the newly created Role to the Pod’s ServiceAccount.

NO.30 SIMULATION
a. Retrieve the content of the existing secret named default-token-xxxxx in the testing namespace.
Store the value of the token in the token.txt
b. Create a new secret named test-db-secret in the DB namespace with the following content:
username: mysql
password: password@123
Create the Pod name test-db-pod of image nginx in the namespace db that can access test-db-secret via a volume at path /etc/mysql-credentials

NO.31 SIMULATION
Given an existing Pod named test-web-pod running in the namespace test-system Edit the existing Role bound to the Pod’s Service Account named sa-backend to only allow performing get operations on endpoints.
Create a new Role named test-system-role-2 in the namespace test-system, which can perform patch operations, on resources of type statefulsets.
Create a new RoleBinding named test-system-role-2-binding binding the newly created Role to the Pod’s ServiceAccount sa-backend.

NO.32 Enable audit logs in the cluster, To Do so, enable the log backend, and ensure that
1. logs are stored at /var/log/kubernetes/kubernetes-logs.txt.
2. Log files are retained for 5 days.
3. at maximum, a number of 10 old audit logs files are retained.
Edit and extend the basic policy to log:
1. Cronjobs changes at RequestResponse
2. Log the request body of deployments changes in the namespace kube-system.
3. Log all other resources in core and extensions at the Request level.
4. Don’t log watch requests by the “system:kube-proxy” on endpoints or

NO.33 Create a PSP that will only allow the persistentvolumeclaim as the volume type in the namespace restricted.
Create a new PodSecurityPolicy named prevent-volume-policy which prevents the pods which is having different volumes mount apart from persistentvolumeclaim.
Create a new ServiceAccount named psp-sa in the namespace restricted.
Create a new ClusterRole named psp-role, which uses the newly created Pod Security Policy prevent-volume-policy Create a new ClusterRoleBinding named psp-role-binding, which binds the created ClusterRole psp-role to the created SA psp-sa.
Hint:
Also, Check the Configuration is working or not by trying to Mount a Secret in the pod maifest, it should get failed.
POD Manifest:
apiVersion: v1
kind: Pod
metadata:
name:
spec:
containers:
– name:
image:
volumeMounts:
– name:
mountPath:
volumes:
– name:
secret:
secretname:

NO.34 Using the runtime detection tool Falco, Analyse the container behavior for at least 30 seconds, using filters that detect newly spawning and executing processes

NO.35 Context: Cluster: gvisor Master node: master1 Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context gvisor
Context: This cluster has been prepared to support runtime handler, runsc as well as traditional one.
Task: Create a RuntimeClass named not-trusted using the prepared runtime handler names runsc. Update all Pods in the namespace server to run on newruntime.

NO.36 Create a PSP that will prevent the creation of privileged pods in the namespace.
Create a new PodSecurityPolicy named prevent-privileged-policy which prevents the creation of privileged pods.
Create a new ServiceAccount named psp-sa in the namespace default.
Create a new ClusterRole named prevent-role, which uses the newly created Pod Security Policy prevent-privileged-policy.
Create a new ClusterRoleBinding named prevent-role-binding, which binds the created ClusterRole prevent-role to the created SA psp-sa.
Also, Check the Configuration is working or not by trying to Create a Privileged pod, it should get failed.

NO.37 Create a RuntimeClass named untrusted using the prepared runtime handler named runsc.
Create a Pods of image alpine:3.13.2 in the Namespace default to run on the gVisor runtime class.

NO.38 You can switch the cluster/configuration context using the following command: [desk@cli] $ kubectl config use-context qa Context: A pod fails to run because of an incorrectly specified ServiceAccount Task: Create a new service account named backend-qa in an existing namespace qa, which must not have access to any secret. Edit the frontend pod yaml to use backend-qa service account Note: You can find the frontend pod yaml at /home/cert_masters/frontend-pod.yaml

NO.39 You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context prod-account
Context:
A Role bound to a Pod’s ServiceAccount grants overly permissive permissions. Complete the following tasks to reduce the set of permissions.
Task:
Given an existing Pod named web-pod running in the namespace database.
1. Edit the existing Role bound to the Pod’s ServiceAccount test-sa to only allow performing get operations, only on resources of type Pods.
2. Create a new Role named test-role-2 in the namespace database, which only allows performing update operations, only on resources of type statuefulsets.
3. Create a new RoleBinding named test-role-2-bind binding the newly created Role to the Pod’s ServiceAccount.
Note: Don’t delete the existing RoleBinding.

NO.40 On the Cluster worker node, enforce the prepared AppArmor profile
#include <tunables/global>
profile docker-nginx flags=(attach_disconnected,mediate_deleted) {
#include <abstractions/base>
network inet tcp,
network inet udp,
network inet icmp,
deny network raw,
deny network packet,
file,
umount,
deny /bin/** wl,
deny /boot/** wl,
deny /dev/** wl,
deny /etc/** wl,
deny /home/** wl,
deny /lib/** wl,
deny /lib64/** wl,
deny /media/** wl,
deny /mnt/** wl,
deny /opt/** wl,
deny /proc/** wl,
deny /root/** wl,
deny /sbin/** wl,
deny /srv/** wl,
deny /tmp/** wl,
deny /sys/** wl,
deny /usr/** wl,
audit /** w,
/var/run/nginx.pid w,
/usr/sbin/nginx ix,
deny /bin/dash mrwklx,
deny /bin/sh mrwklx,
deny /usr/bin/top mrwklx,
capability chown,
capability dac_override,
capability setuid,
capability setgid,
capability net_bind_service,
deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
# deny write to files not in /proc/<number>/** or /proc/sys/**
deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w, deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel) deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/ deny @{PROC}/sysrq-trigger rwklx, deny @{PROC}/mem rwklx, deny @{PROC}/kmem rwklx, deny @{PROC}/kcore rwklx, deny mount, deny /sys/[^f]*/** wklx, deny /sys/f[^s]*/** wklx, deny /sys/fs/[^c]*/** wklx, deny /sys/fs/c[^g]*/** wklx, deny /sys/fs/cg[^r]*/** wklx, deny /sys/firmware/** rwklx, deny /sys/kernel/security/** rwklx,
}
Edit the prepared manifest file to include the AppArmor profile.
apiVersion: v1
kind: Pod
metadata:
name: apparmor-pod
spec:
containers:
– name: apparmor-pod
image: nginx
Finally, apply the manifests files and create the Pod specified on it.
Verify: Try to use command ping, top, sh

NO.41 SIMULATION
On the Cluster worker node, enforce the prepared AppArmor profile
#include <tunables/global>
profile docker-nginx flags=(attach_disconnected,mediate_deleted) {
#include <abstractions/base>
network inet tcp,
network inet udp,
network inet icmp,
deny network raw,
deny network packet,
file,
umount,
deny /bin/** wl,
deny /boot/** wl,
deny /dev/** wl,
deny /etc/** wl,
deny /home/** wl,
deny /lib/** wl,
deny /lib64/** wl,
deny /media/** wl,
deny /mnt/** wl,
deny /opt/** wl,
deny /proc/** wl,
deny /root/** wl,
deny /sbin/** wl,
deny /srv/** wl,
deny /tmp/** wl,
deny /sys/** wl,
deny /usr/** wl,
audit /** w,
/var/run/nginx.pid w,
/usr/sbin/nginx ix,
deny /bin/dash mrwklx,
deny /bin/sh mrwklx,
deny /usr/bin/top mrwklx,
capability chown,
capability dac_override,
capability setuid,
capability setgid,
capability net_bind_service,
deny @{PROC}/* w, # deny write for all files directly in /proc (not in a subdir)
# deny write to files not in /proc/<number>/** or /proc/sys/**
deny @{PROC}/{[^1-9],[^1-9][^0-9],[^1-9s][^0-9y][^0-9s],[^1-9][^0-9][^0-9][^0-9]*}/** w, deny @{PROC}/sys/[^k]** w, # deny /proc/sys except /proc/sys/k* (effectively /proc/sys/kernel) deny @{PROC}/sys/kernel/{?,??,[^s][^h][^m]**} w, # deny everything except shm* in /proc/sys/kernel/ deny @{PROC}/sysrq-trigger rwklx, deny @{PROC}/mem rwklx, deny @{PROC}/kmem rwklx, deny @{PROC}/kcore rwklx, deny mount, deny /sys/[^f]*/** wklx, deny /sys/f[^s]*/** wklx, deny /sys/fs/[^c]*/** wklx, deny /sys/fs/c[^g]*/** wklx, deny /sys/fs/cg[^r]*/** wklx, deny /sys/firmware/** rwklx, deny /sys/kernel/security/** rwklx,
}
Edit the prepared manifest file to include the AppArmor profile.
apiVersion: v1
kind: Pod
metadata:
name: apparmor-pod
spec:
containers:
– name: apparmor-pod
image: nginx
Finally, apply the manifests files and create the Pod specified on it.
Verify: Try to use command ping, top, sh

NO.42 Cluster: scanner Master node: controlplane Worker node: worker1
You can switch the cluster/configuration context using the following command:
[desk@cli] $ kubectl config use-context scanner
Given: You may use Trivy’s documentation.
Task: Use the Trivy open-source container scanner to detect images with severe vulnerabilities used by Pods in the namespace nato.
Look for images with High or Critical severity vulnerabilities and delete the Pods that use those images. Trivy is pre-installed on the cluster’s master node. Use cluster’s master node to use Trivy.