Securing Kubernetes in Azure

Introduction

• Securing an Azure Kubernetes Service (AKS) cluster involves multiple layers of security to protect the cluster, workloads, and data.
• Below are key steps and best practices to secure your AKS cluster:

1. Network Security

• Use Network Policies: Implement network policies to control traffic flow between pods.
• Restrict API Server Access: Limit access to the Kubernetes API server by using authorized IP ranges.
• Private AKS Clusters: Deploy private AKS clusters to restrict access to the API server to within the virtual network.
• Network Security Groups (NSGs): Use NSGs to control inbound and outbound traffic to resources in the virtual network.

2. Identity and Access Management (IAM)

• Azure Active Directory (AD) Integration: Integrate AKS with Azure AD for centralized identity and access management.
• Role-Based Access Control (RBAC): Use Kubernetes RBAC to control access to cluster resources.
• Azure AD RBAC: Assign Azure AD roles to control access to Azure resources associated with the AKS cluster.
• Least Privilege Principle: Grant the minimum permissions required for users and applications.

3. Cluster Configuration

• Use Managed Identities: Utilize managed identities for Azure resources to secure interactions with other Azure services.
• Secrets Management: Store Kubernetes secrets in Azure Key Vault instead of in-cluster.
• Pod Security Policies: Define and enforce pod security policies to control pod creation and enforce security standards.
• Enable HTTP Application Routing Add-on: Use the add-on for DNS management and HTTPS certificates.

4. Image Security

• Scan Container Images: Regularly scan container images for vulnerabilities using tools like Azure Security Center or third-party scanners.
• Use Trusted Registries: Pull images only from trusted container registries.
• Update and Patch: Ensure container images are up to date with the latest security patches.

5. Security Monitoring and Logging

• Enable Azure Monitor: Use Azure Monitor for containers to collect and analyze metrics and logs from AKS clusters.
• Azure Security Center: Enable Azure Security Center to provide unified security management and advanced threat protection across hybrid cloud workloads.
• Audit Logs: Enable audit logging in Kubernetes to keep track of access and changes to the cluster.

6. Network Segmentation

• Use Azure Virtual Network (VNet): Isolate AKS clusters within a VNet and segment traffic using subnets.
• Application Gateway and WAF: Deploy an Azure Application Gateway with a Web Application Firewall (WAF) to protect HTTP/HTTPS services.

7. Data Protection

• Encrypt Data at Rest: Ensure that data stored in Azure Disk and Azure Files is encrypted at rest.
• Encrypt Data in Transit: Use TLS to encrypt data in transit between components.

8. Operational Security

• Backup and Disaster Recovery: Implement a backup strategy for cluster configuration and persistent volumes using tools like Velero.
• Regular Audits: Conduct regular security audits and vulnerability assessments of the AKS cluster.
• Compliance Checks: Ensure compliance with industry standards and regulatory requirements.

9. Pod Security

• Resource Quotas and Limits: Define resource quotas and limits to prevent resource exhaustion attacks.
• Namespace Isolation: Use namespaces to separate different environments and teams within the same cluster.
• Security Contexts: Configure security contexts for pods and containers to enforce security constraints.

10. Additional Security Measures

• Azure Policy: Use Azure Policy to enforce organizational standards and assess compliance at-scale.
• Azure DevOps Integration: Integrate with Azure DevOps for secure CI/CD pipelines, including security checks in the build and release process.
• Periodic Reviews: Conduct periodic reviews of cluster configurations, network settings, and access controls.