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Certified Kubernetes Security Specialist (CKS) Study Guide

Name: Certified Kubernetes Security Specialist (CKS) Study Guide
Author: Benjamin Muschko
ISBN: 9781098132972

by Benjamin Muschko

June 2023

Intermediate to advanced

211 pages

5h 8m

English

O'Reilly Media, Inc.

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Preface
Who This Book Is ForWhat You Will LearnStructure of This BookConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgments
1. Exam Details and Resources
Kubernetes Certification Learning PathKubernetes and Cloud Native Associate (KCNA)Kubernetes and Cloud Native Security Associate (KCSA)Certified Kubernetes Application Developer (CKAD)Certified Kubernetes Administrator (CKA)Certified Kubernetes Security Specialist (CKS)Exam ObjectivesCurriculumCluster SetupCluster HardeningSystem HardeningMinimize Microservice VulnerabilitiesSupply Chain SecurityMonitoring, Logging, and Runtime SecurityInvolved Kubernetes PrimitivesInvolved External ToolsDocumentationCandidate SkillsPracticing and Practice ExamsSummary
2. Cluster Setup
Using Network Policies to Restrict Pod-to-Pod CommunicationScenario: Attacker Gains Access to a PodObserving the Default BehaviorDenying Directional Network TrafficAllowing Fine-Grained Incoming TrafficApplying Kubernetes Component Security Best PracticesUsing kube-benchThe kube-bench Verification ResultFixing Detected Security IssuesCreating an Ingress with TLS TerminationSetting Up the Ingress BackendCreating the TLS Certificate and KeyCreating the TLS-Typed SecretCreating the IngressCalling the IngressProtecting Node Metadata and EndpointsScenario: A Compromised Pod Can Access the Metadata ServerProtecting Metadata Server Access with Network PoliciesProtecting GUI ElementsScenario: An Attacker Gains Access to the Dashboard FunctionalityInstalling the Kubernetes DashboardAccessing the Kubernetes DashboardCreating a User with Administration PrivilegesCreating a User with Restricted PrivilegesAvoiding Insecure Configuration ArgumentsVerifying Kubernetes Platform BinariesScenario: An Attacker Injected Malicious Code into BinaryVerifying a Binary Against HashSummaryExam EssentialsSample Exercises
3. Cluster Hardening
Interacting with the Kubernetes APIProcessing a RequestConnecting to the API ServerRestricting Access to the API ServerScenario: An Attacker Can Call the API Server from the InternetRestricting User PermissionsScenario: An Attacker Can Call the API Server from a Service AccountMinimizing Permissions for a Service AccountUpdating Kubernetes FrequentlyVersioning SchemeRelease CadencePerforming the Upgrade ProcessSummaryExam EssentialsSample Exercises
4. System Hardening
Minimizing the Host OS FootprintScenario: An Attacker Exploits a Package VulnerabilityDisabling ServicesRemoving Unwanted PackagesMinimizing IAM RolesScenario: An Attacker Uses Credentials to Gain File AccessUnderstanding User ManagementUnderstanding Group ManagementUnderstanding File Permissions and OwnershipMinimizing External Access to the NetworkIdentifying and Disabling Open PortsSetting Up Firewall RulesUsing Kernel Hardening ToolsUsing AppArmorUsing seccompSummaryExam EssentialsSample Exercises
5. Minimizing Microservice Vulnerabilities
Setting Appropriate OS-Level Security DomainsScenario: An Attacker Misuses root User Container AccessUnderstanding Security ContextsEnforcing the Usage of a Non-Root UserSetting a Specific User and Group IDAvoiding Privileged ContainersScenario: A Developer Doesn’t Follow Pod Security Best PracticesUnderstanding Pod Security Admission (PSA)Enforcing Pod Security Standards for a NamespaceUnderstanding Open Policy Agent (OPA) and GatekeeperInstalling GatekeeperImplementing an OPA PolicyManaging SecretsScenario: An Attacker Gains Access to the Node Running etcdAccessing etcd DataEncrypting etcd DataUnderstanding Container Runtime SandboxesScenario: An Attacker Gains Access to Another ContainerAvailable Container Runtime Sandbox ImplementationsInstalling and Configuring gVisorCreating and Using a Runtime ClassUnderstanding Pod-to-Pod Encryption with mTLSScenario: An Attacker Listens to the Communication Between Two PodsAdopting mTLS in KubernetesSummaryExam EssentialsSample Exercises
6. Supply Chain Security
Minimizing the Base Image FootprintScenario: An Attacker Exploits Container VulnerabilitiesPicking a Base Image Small in SizeUsing a Multi-Stage Approach for Building Container ImagesReducing the Number of LayersUsing Container Image Optimization ToolsSecuring the Supply ChainSigning Container ImagesScenario: An Attacker Injects Malicious Code into a Container ImageValidating Container ImagesUsing Public Image RegistriesScenario: An Attacker Uploads a Malicious Container ImageWhitelisting Allowed Image Registries with OPA GateKeeperWhitelisting Allowed Image Registries with the ImagePolicyWebhook Admission Controller PluginImplementing the Backend ApplicationConfiguring the ImagePolicyWebhook Admission Controller PluginStatic Analysis of WorkloadUsing Hadolint for Analyzing DockerfilesUsing Kubesec for Analyzing Kubernetes ManifestsScanning Images for Known VulnerabilitiesSummaryExam EssentialsSample Exercises
7. Monitoring, Logging, and Runtime Security
Performing Behavior AnalyticsScenario: A Kubernetes Administrator Can Observe Actions Taken by an AttackerUnderstanding FalcoInstalling FalcoConfiguring FalcoGenerating Events and Inspecting Falco LogsUnderstanding Falco Rule File BasicsOverriding Existing RulesEnsuring Container ImmutabilityScenario: An Attacker Installs Malicious SoftwareUsing a Distroless Container ImageConfiguring a Container with a ConfigMap or SecretConfiguring a Read-Only Container Root FilesystemUsing Audit Logs to Monitor AccessScenario: An Administrator Can Monitor Malicious Events in Real TimeUnderstanding Audit LogsCreating the Audit Policy FileConfiguring a Log BackendConfiguring a Webhook BackendSummaryExam EssentialsSample Exercises
Appendix. Answers to Review Questions
Chapter 2, “Cluster Setup”Chapter 3, “Cluster Hardening”Chapter 4, “System Hardening”Chapter 5, “Minimize Microservice Vulnerabilities”Chapter 6, “Supply Chain Security”Chapter 7, “Monitoring, Logging, and Runtime Security”
Index

About the Author

Content preview from Certified Kubernetes Security Specialist (CKS) Study Guide

Chapter 3. Cluster Hardening

The domain “cluster hardening” touches on topics important to keep a cluster as secure as possible once it has been set up and configured initially. As part of the discussion of this chapter, you may notice that I will reference concepts and practices that usually fall into the hands of Kubernetes administrators. Where appropriate, I will provide links to the topics that have already been covered by the CKA exam.

At a high level, this chapter covers the following concepts:

Restricting access to the Kubernetes API
Configuring role-based access control (RBAC) to minimize exposure
Exercising caution in using service accounts
Updating Kubernetes frequently

Interacting with the Kubernetes API

The API server is the gateway to the Kubernetes cluster. Any human user, client (e.g., kubectl), cluster component, or service account will access the API server by making a RESTful API call via HTTPS. It is the central point for performing operations like creating a Pod, or deleting a Service.

In this section, we’ll only focus on the security-specific aspects relevant to the API server. For a detailed discussion on the inner workings of the API server and the usage of the Kubernetes API, refer to the book Managing Kubernetes by Brendan Burns and Craig Tracey (O’Reilly).

Processing a Request

Figure 3-1 illustrates the stages a request goes through when a call is made to the API server. For reference, you can find more information in the Kubernetes documentation ...

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