Security & Compliance

Securing Kubernetes at enterprise scale requires a comprehensive approach spanning infrastructure, workloads, data, and access controls. This guide outlines security best practices and compliance strategies for production Kubernetes environments.

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Defense-in-Depth Security Model

Enterprise Kubernetes security follows a layered approach:

┌─────────────────────────────────────────────────────┐
│ Cluster Infrastructure Security                     │
├─────────────────────────────────────────────────────┤
│ Kubernetes Control Plane Security                   │
├─────────────────────────────────────────────────────┤
│ Network Security & Segmentation                     │
├─────────────────────────────────────────────────────┤
│ Workload Security (Pods & Containers)               │
├─────────────────────────────────────────────────────┤
│ Data Security & Secrets Management                  │
├─────────────────────────────────────────────────────┤
│ Authentication & Authorization (IAM)                │
├─────────────────────────────────────────────────────┤
│ Audit Logging & Monitoring                          │
├─────────────────────────────────────────────────────┤
│ Compliance & Governance                             │
└─────────────────────────────────────────────────────┘

---

Cluster Infrastructure Hardening

Private Cluster Architecture

Implement security best practices at the infrastructure level:

┌─────────────────────────────────────────────────────────┐
│                     Private VPC/VNET                    │
│                                                         │
│  ┌─────────────────┐                                    │
│  │ Bastion Host/   │                                    │
│  │ VPN Gateway     │                                    │
│  └────────┬────────┘                                    │
│           │                                             │
│  ┌────────▼─────────────────────────────────────┐       │
│  │           Private Kubernetes Cluster         │       │
│  │                                              │       │
│  │   ┌──────────────┐      ┌──────────────┐     │       │
│  │   │ Control Plane│      │ Worker Nodes │     │       │
│  │   └──────────────┘      └──────────────┘     │       │
│  └──────────────────────────────────────────────┘       │
│                                                         │
└─────────────────────────────────────────────────────────┘

Cloud-Specific Recommendations

AWS EKS:

• Enable envelope encryption of EKS secrets using AWS KMS

• Use Security Groups to restrict traffic between nodes

• Implement private endpoint access for the EKS API

• Use EC2 instances with IMDSv2 for node groups

Azure AKS:

• Deploy AKS with Azure Private Link

• Implement Azure Service Endpoints for service connections

• Use Azure Policy for AKS security controls

• Enable Azure Defender for Kubernetes

Google GKE:

• Deploy private GKE clusters

• Use VPC Service Controls to restrict API access

• Enable Shielded GKE Nodes

• Implement Binary Authorization

---

Kubernetes-Native Security Controls

Pod Security Standards

Enforce pod security using the built-in Pod Security Standards:

apiVersion: v1
kind: Namespace
metadata:
  name: restricted-namespace
  labels:
    pod-security.kubernetes.io/enforce: restricted
    pod-security.kubernetes.io/audit: restricted
    pod-security.kubernetes.io/warn: restricted

Policy Enforcement with OPA Gatekeeper

Deploy policy guardrails with OPA Gatekeeper:

apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sRequiredLabels
metadata:
  name: require-team-label
spec:
  match:
    kinds:
      - apiGroups: [""]
        kinds: ["Namespace"]
  parameters:
    labels: ["team", "environment", "application"]

Image Scanning and Admission Control

apiVersion: v1
kind: ConfigMap
metadata:
  name: trivy-operator-policies
  namespace: trivy-system
data:
  policy.yaml: |
    package trivy
    
    deny[msg] {
      input.vulnerabilities[_].Severity == "CRITICAL"
      msg := "Critical vulnerabilities are not allowed"
    }
    
    deny[msg] {
      input.securityIssues[_].Severity == "HIGH"
      msg := "Images with high security issues are not allowed"
    }

---

Network Security

Core Network Security Components

┌──────────────────────────────────────────┐
│              Egress Firewall             │
└──────────────────┬───────────────────────┘
                   │
┌──────────────────▼───────────────────────┐
│              Ingress Controller          │
│              with WAF/DDoS               │
└──────────────────┬───────────────────────┘
                   │
┌──────────────────▼───────────────────────┐
│              Service Mesh                │
│         (East-West Traffic Control)      │
└──────────────────┬───────────────────────┘
                   │
┌──────────────────▼───────────────────────┐
│           Network Policies               │
│           (Pod-level Firewalls)          │
└──────────────────────────────────────────┘

Network Policy Implementation

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: backend-policy
  namespace: production
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 8080
  egress:
  - to:
    - namespaceSelector:
        matchLabels:
          purpose: database
      podSelector:
        matchLabels:
          app: postgres
    ports:
    - protocol: TCP
      port: 5432

Service Mesh Security (Istio Example)

apiVersion: security.istio.io/v1beta1
kind: PeerAuthentication
metadata:
  name: default
  namespace: istio-system
spec:
  mtls:
    mode: STRICT
---
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: allow-specific-methods
  namespace: production
spec:
  selector:
    matchLabels:
      app: backend
  action: ALLOW
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/default/sa/frontend-service-account"]
    to:
    - operation:
        methods: ["GET", "POST"]
        paths: ["/api/v1/*"]

---

Secret Management

External Secret Management Integration

# Using External Secrets Operator with AWS Secrets Manager
apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
  name: database-credentials
  namespace: production
spec:
  refreshInterval: "15m"
  secretStoreRef:
    name: aws-secretsmanager
    kind: ClusterSecretStore
  target:
    name: database-credentials
  data:
  - secretKey: username
    remoteRef:
      key: production/database
      property: username
  - secretKey: password
    remoteRef:
      key: production/database
      property: password

Sealed Secrets for GitOps

apiVersion: bitnami.com/v1alpha1
kind: SealedSecret
metadata:
  name: api-key
  namespace: production
spec:
  encryptedData:
    api-key: AgBy8hCNjjSa...truncated...P8kQ9H3mAyxF3A

---

Authentication & Authorization

RBAC Implementation Best Practices

Principle of Least Privilege:

# Team-specific role with limited permissions
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: team-a
  name: team-a-developer
rules:
- apiGroups: [""]
  resources: ["pods", "services", "configmaps", "secrets"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
- apiGroups: ["apps"]
  resources: ["deployments", "statefulsets"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
---
# Bind role to team group from identity provider
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: team-a-developers
  namespace: team-a
subjects:
- kind: Group
  name: "ad:team-a-developers"
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: team-a-developer
  apiGroup: rbac.authorization.k8s.io

SSO Integration with OIDC

# Using OIDC with Azure AD for AKS
apiVersion: v1
kind: ConfigMap
metadata:
  name: azure-ad-oidc-config
  namespace: kube-system
data:
  oidc-client-id: "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
  oidc-issuer-url: "https://sts.windows.net/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/"
  oidc-username-claim: "email"
  oidc-groups-claim: "groups"

---

Audit Logging & Monitoring

Enhanced Audit Policy

apiVersion: audit.k8s.io/v1
kind: Policy
rules:
# Log all requests at the Metadata level
- level: Metadata
  # Long-running requests like watches that aren't recorded at RequestReceived
  omitStages:
    - "RequestReceived"
# Log pod changes at RequestResponse level
- level: RequestResponse
  resources:
  - group: ""
    resources: ["pods"]
# Log auth at RequestResponse level
- level: RequestResponse
  resources:
  - group: "authentication.k8s.io"
    resources: ["*"]
# Log all other resources at the Metadata level
- level: Metadata
  # Long-running requests like watches that aren't recorded at RequestReceived
  omitStages:
    - "RequestReceived"

Security-Focused Monitoring

# Falco security monitoring
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: falco
  namespace: security
spec:
  selector:
    matchLabels:
      app: falco
  template:
    metadata:
      labels:
        app: falco
    spec:
      containers:
      - name: falco
        image: falcosecurity/falco:latest
        securityContext:
          privileged: true
        volumeMounts:
        - mountPath: /var/run/docker.sock
          name: docker-socket
        - mountPath: /host/var/run/docker.sock
          name: docker-socket
        - mountPath: /host/dev
          name: dev-fs
        - mountPath: /host/proc
          name: proc-fs
          readOnly: true
        - mountPath: /host/boot
          name: boot-fs
          readOnly: true
        - mountPath: /host/lib/modules
          name: lib-modules
          readOnly: true
        - mountPath: /host/usr
          name: usr-fs
          readOnly: true
        - mountPath: /etc/falco
          name: falco-config
      volumes:
      - name: docker-socket
        hostPath:
          path: /var/run/docker.sock
      - name: dev-fs
        hostPath:
          path: /dev
      - name: proc-fs
        hostPath:
          path: /proc
      - name: boot-fs
        hostPath:
          path: /boot
      - name: lib-modules
        hostPath:
          path: /lib/modules
      - name: usr-fs
        hostPath:
          path: /usr
      - name: falco-config
        configMap:
          name: falco-config

---

Compliance Automation

Continuous Compliance Validation

# Kyverno policy for PCI-DSS compliance
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: pci-dss-restricted
spec:
  validationFailureAction: Enforce
  rules:
  - name: host-path-volumes-restricted
    match:
      resources:
        kinds:
        - Pod
    validate:
      message: "Host path volumes are not allowed for PCI-DSS compliance"
      pattern:
        spec:
          =(volumes):
            - =(hostPath): "null"
  - name: require-pod-probes
    match:
      resources:
        kinds:
        - Deployment
    validate:
      message: "Liveness and readiness probes are required"
      pattern:
        spec:
          template:
            spec:
              containers:
              - livenessProbe:
                  =(httpGet):
                    path: "*"
                    port: "*"
                readinessProbe:
                  =(httpGet):
                    path: "*"
                    port: "*"

Compliance Scanning and Reporting

# Trivy Operator configuration for vulnerability reporting
apiVersion: aquasecurity.github.io/v1alpha1
kind: VulnerabilityReport
metadata:
  name: app-vulnerability-report
  namespace: compliance
spec:
  target:
    resource:
      apiVersion: apps/v1
      kind: Deployment
      name: web-application
      namespace: production
  scanner:
    name: Trivy
    parameters:
      - name: "ignoreUnfixed"
        value: "true"
      - name: "severity"
        value: "CRITICAL,HIGH"
  schedule: "0 */6 * * *" # Every 6 hours

---

Disaster Recovery & Security Incident Response

Security Incident Response Plan

1. Detection: Monitor security alerts from:

   • Kubernetes audit logs

   • Container runtime security tools (Falco)

   • Cloud provider security services

2. Containment:

   # Isolate compromised namespace
   kubectl label namespace compromised security=isolated
   kubectl apply -f isolate-network-policy.yaml
   
   # Force restart suspicious pods
   kubectl delete pod suspicious-pod-xyz -n compromised
   
   # Temporarily disable compromised service account
   kubectl patch serviceaccount -n compromised compromised-sa \
     -p '{"metadata":{"annotations":{"security.alpha.kubernetes.io/disabled":"true"}}}'

3. Eradication & Recovery:

   # Rotate credentials
   kubectl create secret generic app-credentials --from-literal=password=$(openssl rand -base64 32) -n compromised --dry-run=client -o yaml | kubectl apply -f -
   
   # Apply updated security policies
   kubectl apply -f updated-pod-security-policies.yaml
   
   # Restore from known good state
   kubectl apply -f https://gitops-repo/known-good-state.yaml

4. Post-Incident Analysis:

   • Forensic analysis of compromised containers

   • Audit log review

   • Root cause identification and remediation

---

Cloud-Specific Compliance Controls

AWS EKS Compliance

Requirement	Implementation
Access Logging	AWS CloudTrail + EKS audit logs to CloudWatch
Data Encryption	EBS encryption with KMS for PVs
Network Segmentation	Security Groups, NACLs, and K8s NetworkPolicies
Vulnerability Management	Amazon Inspector + ECR image scanning
Compliance Reporting	AWS Config Rules + AWS Security Hub

Azure AKS Compliance

Requirement	Implementation
Access Logging	Azure Monitor + AKS diagnostic settings
Data Encryption	Azure Disk Encryption + Azure Key Vault
Network Segmentation	NSGs, Azure Firewall, and K8s NetworkPolicies
Vulnerability Management	Microsoft Defender for Containers
Compliance Reporting	Azure Policy for AKS + Azure Security Center

GCP GKE Compliance

Requirement	Implementation
Access Logging	Cloud Audit Logs + GKE audit logging
Data Encryption	Application-layer encryption with Cloud KMS
Network Segmentation	VPC Firewalls and K8s NetworkPolicies
Vulnerability Management	GKE container threat detection + Binary Authorization
Compliance Reporting	Security Command Center + Compliance Reports

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References

• CIS Kubernetes Benchmark
• NIST Application Container Security Guide
• Kubernetes Security Cheat Sheet
• NSA Kubernetes Hardening Guide
• CNCF Cloud Native Security Whitepaper