abdennour / certified-kubernetes-security-specialist

References for CKS Exam Objectives - Certified Kubernetes Security Specialist

Cluster Setup – 10%

Use Network security policies to restrict cluster level access

• https://kubernetes.io/docs/concepts/services-networking/network-policies/
• 🔬 https://github.com/ahmetb/kubernetes-network-policy-recipes
• https://medium.com/@reuvenharrison/an-introduction-to-kubernetes-network-policies-for-security-people-ba92dd4c809d
• https://github.com/Tufin/test-network-policies

Use CIS benchmark to review the security configuration of Kubernetes components (etcd, kubelet, kubedns, kubeapi)

# install kube-bench in the current host dir
docker run --rm -it -v `pwd`:/host aquasec/kube-bench:latest install

# benchmarking your cluster ( verify the curren kubeconfig before)
./kube-bench <name-of-node>

• https://www.cisecurity.org/benchmark/kubernetes/
• https://github.com/dev-sec/cis-kubernetes-benchmark
• https://github.com/aquasecurity/kube-bench
• https://cloud.google.com/kubernetes-engine/docs/concepts/cis-benchmarks

Properly set up Ingress objects with security control

• secure an Ingress by specifying a Secret that contains a TLS private key and certificate

Protect node metadata and endpoints

• Prevent unauthenticated / unauthorised to api-server (authorization-mode, .. son on)

Minimize use of, and access to, GUI elements

• https://blog.heptio.com/on-securing-the-kubernetes-dashboard-16b09b1b7aca

Verify platform binaries before deploying

• https://github.com/kubernetes/kubernetes/releases

Cluster Hardening – 15%

Restrict access to Kubernetes API

• Controlling Access to the Kubernetes API : https://kubernetes.io/docs/reference/access-authn-authz/controlling-access/

Use Role Based Access Controls to minimize exposure

• https://kubernetes.io/docs/reference/access-authn-authz/rbac/
• https://github.com/David-VTUK/CKA-StudyGuide/blob/master/RevisionTopics/Part-5-Security.md

Exercise caution in using service accounts e.g. disable defaults, minimize permissions on newly created ones

• https://kubernetes.io/docs/reference/access-authn-authz/service-accounts-admin/
• https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/

Update Kubernetes frequently

• https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/

System Hardening – 15%

Minimize host OS footprint (reduce attack surface)

• CIS benchmark Overview/General

• CIS benchmark dedicated for each distribution

• https://www.cisecurity.org/benchmark/red_hat_linux/
• https://www.cisecurity.org/benchmark/ubuntu_linux/
• https://www.cisecurity.org/benchmark/centos_linux/
• https://www.cisecurity.org/benchmark/debian_linux/
• https://www.cisecurity.org/benchmark/suse_linux/
• https://www.cisecurity.org/benchmark/oracle_linux/

Minimize IAM roles

• Least privilege pincipal is generally the way to go!

Minimize external access to the network

• ACL at the level of subnet : https://docs.aws.amazon.com/vpc/latest/userguide/vpc-network-acls.html
• Security Group at the level of machine : https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-security-groups.html
• Firewall at the level of OS ( ufw, firewall-cmd ) : https://www.linode.com/docs/security/firewalls/configure-firewall-with-ufw/

Appropriately use kernel hardening tools such as AppArmor, seccomp

• https://kubernetes.io/docs/tutorials/clusters/apparmor/

• https://kubernetes.io/docs/tutorials/clusters/seccomp/

• 📚 "Container Security" by Liz Rice which covers AppArmor, Seccomp, SELinux and the whole gang.

Minimize Microservice Vulnerabilities – 20%

Setup appropriate OS level security domains e.g. using PSP, OPA, security contexts

• PSP : https://kubernetes.io/docs/concepts/policy/pod-security-policy/

• OPA : https://www.openpolicyagent.org/docs/latest/kubernetes-primer/

• Security Context : https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

Manage Kubernetes secrets

• https://kubernetes.io/docs/concepts/configuration/secret/

• 📹 TGIK - Advanced k8s secret management : https://www.youtube.com/watch?v=IznsHhKL428&ab_channel=VMwareCloudNativeApps

• 🔬 Sealed Secrets : https://github.com/bitnami-labs/sealed-secrets

• secrets-store-csi-driver : https://github.com/kubernetes-sigs/secrets-store-csi-driver

• https://spacelift.io/blog/kubernetes-secrets

Use container runtime sandboxes in multi-tenant environments (e.g. gvisor, kata containers)

• gVisor : https://gvisor.dev/docs/user_guide/install/

• kata : https://github.com/kata-containers/kata-containers

• 🔬 Hands-on Kata : https://github.com/abdennour/abdennour.github.io/blob/master/_posts/2018-06-09-successfully-running-kata-containers-in-the-cloud.markdown

Implement pod to pod encryption by use of mTLS

• https://kubernetes.io/docs/tasks/tls/managing-tls-in-a-cluster/

• Using istio , https://developer.ibm.com/technologies/containers/tutorials/istio-security-mtls/

• Using linkerd, https://linkerd.io/2/features/automatic-mtls/

• 🔬 https://www.istioworkshop.io/11-security/01-mtls/

Supply Chain Security – 20%

Minimize base image footprint

• 7 best practices for build containers.

• https://github.com/GoogleContainerTools/distroless

Secure your supply chain: whitelist allowed registries, sign and validate images

• Docker Way : https://docs.docker.com/engine/security/trust/content_trust/

• Tools for manage supply chain and artifacts:

• tools for siging container image Cryptographically:

• example - restrict pulling images from registries

• Related also with https://kubernetes.io/blog/2019/03/21/a-guide-to-kubernetes-admission-controllers/

Use static analysis of user workloads (e.g.Kubernetes resources, Docker files)

• kubehunter: https://github.com/aquasecurity/kube-hunter
• Tools around static container image scan:

Scan images for known vulnerabilities

• Clair: https://github.com/quay/clair

• Tools around dynamic container image scan :

Monitoring, Logging and Runtime Security – 20%

Perform behavioral analytics of syscall process and file activities at the host and container level to detect malicious activities

• https://kubernetes.io/docs/tutorials/clusters/seccomp/

Detect threats within physical infrastructure, apps, networks, data, users and workloads

Detect all phases of attack regardless where it occurs and how it spreads

• Get the General Concept : https://www.dnvgl.com/article/the-seven-phases-of-a-cyber-attack-118270

Perform deep analytical investigation and identification of bad actors within environment

Ensure immutability of containers at runtime

• Falco might help ?

Use Audit Logs to monitor access

• https://kubernetes.io/docs/tasks/debug-application-cluster/audit/

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Other links :

• SIG security - MoM

• Firecracker for multi-tenancy, Bottlerocket to reduce the attack surface, audit2rbac for generating RBAC roles

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Disclaimer

The given links are our assumptions and ideas - we neither have insights into the exam requirements, nor do we know how exactly it will look like. We are guessing about possibilities and try to collect resources.

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