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Kubernetes Security Best Practices and Tools

Gursimran Singh | 28 February 2024

Kubernetes Security Tools and Best Practices

Kubernetes Security for Cloud-Native Environments

Kubernetes has become defecto standard for Container Orchestration in Cloud Native Environments. Its adoption has surpassed all its competitors by huge margin. If we look at Kubernetes environments from security point of view, it has come up with its own set of challenges and remediation.

 

1. Runtime Security Incidents 

2. Misconfigurations

3. Supply Chain Vulnerabilities 

 

The security concerns associated with Kubernetes correspond to container lifecycle stages.

Security is the number one challenge for users adopting Kubernetes, cited by 46% of users (which rises to 55% in larger enterprises). Source, The State of the Kubernetes Ecosystem

Pillars of Kubernetes Security 

It is built on the four Cs of cloud-native security: cloud, cluster, container, and code.

 

1. Cloud

Security is based on the underlying physical infrastructure. Cloud provider (or physical security) best practices must be followed whether the cluster is constructed on one's own data center or a cloud provider. For private cloud the infrastructure tools and process for any datacenter is required, for a public cloud infrastructure the security tools and processes are dependent on the Public Cloud. Every Public Cloud have its own set of services that are focused on its physical security. 

It is highly recommended to use Managed Services available in the Cloud. The three major cloud providers AWS EKS, Azure AKS, GKE are the managed offerings available in each. Using these services would bring the onus of managing Physical Security on Cloud Provider as part of its Shared responsibility model.

 

2. Cluster

Securing a Kubernetes cluster includes securing its control plane components including the Kubernetes APIs. If you are having an unmanaged Kubernetes Cluster deployment, its essential to secure the control plane components, the host with control plane components, the networking of the control plane as well as the containers that are hosting those. If you are using a managed Kubernetes Control plane on public cloud, the onus of securing the control plane is on Cloud provider and it becomes easier to secure it. The Clusters must be upgraded time to time.

 

3. Container

Examples of container design best practices are starting with the most straightforward code base feasible (excluding superfluous libraries or functions), avoiding granting excessive access to users in the container, and ensuring that containers are inspected for vulnerabilities at build time.

 

4. Code

For any Kubernetes setup, code is a large attack surface like other deployment platforms. Proper penetration testing, Dependency Check, Static Code Analysis and Dynamic Code analysis are required to have a clean and secure code. Tools like Sonarqube can be used.   

Why is Kubernetes Security Important? 

Due to the distributed and dynamic nature of a Kubernetes cluster, security is critical throughout the container lifetime. For each of the three phases of an application's lifecycle: build, deploy, and runtime, different security measures are necessary. Kubernetes has built-in security features like Pod Security Policeis, Network Policeis and RBAC that should be used as much as possible. 

Application containers, for example, are rarely patched or updated; instead, container images are entirely replaced with new versions. This allows for strict version control and quick rollbacks if a vulnerability in new code is discovered. 

However, because individual pods are temporary and ephemeral, IT security experts may face issues in the ever-changing runtime environment, as applications and API linkages to other applications and services are continually changing. 

Kubernetes Security Risks 

Kubernetes uses a flat network model by default, that allows each pod to communicate with others in the cluster by default. This creates significant security concerns as it allows attackers to compromise pods and communicate with other resources in the cluster freely.

 

1. Numerous Containers - Containers provide increased speed, portability, and the possibility to use microservices architectures, but they can also introduce security vulnerabilities and increase your attack surface. Maintaining proper insight into your cloud-native infrastructure components becomes more difficult as more containers are deployed.

2. Image Registries pose Security Risks - Organizations require strict governance procedures for creating and storing pictures in trusted image registries. Container images must be produced using secure and approved base images scanned regularly. Only images from image registries on allow lists should be used to launch containers in your Kubernetes system. 

3. Container Endpoints - To perform successfully, containers and pods will need to communicate with one other within deployments and with other internal and external endpoints. The ability of a malicious actor to move laterally within the environment if a container is breached is directly tied to how widely that container can connect with other containers and pods. 

What are the Best Practices for Kubernetes Security Deployment? 

Let us explore the best security practices for Kubernetes Deployment Strategy. While working on the Kubernetes cluster, there are some security practices that we should keep in mind to ensure the security of the deployment process. Some of these security best practices are below: 

Protect your entire clusters with runtime protection of kubernetes workloads by automating security configuration and compliance. Click to explore,Azure Kubernetes Services 

  • Set Security context for Pods and Containers

While designing pods and containers, we need to keep in mind applying security context to your pods and containers. It is a property defined in the deployment YAML. The security context controls the security parameters for the pod or container. For example, we can security context as: SecurityContext->runAsNonRoot. Also, 'DenyEscalatingExec' admission control can be used to deny exec and attach commands to pods if you run pods with escalated privileges. 

  • Use Authorized Images in the Environment

A process to check and ensure that only the images that adhere to the organization's area's policy are used and are allowed to run in your environment. Without this process, there is a significant risk of running malicious or vulnerable containers. It can be dangerous for the organization. The approved images should be stored in private registries. Make sure that these private registries only store approved models and not untrusted images.  

Before pushing the image to the individual record, a built image must be scanned for vulnerabilities. Only pictures, which have no issues or weaknesses, sell only to the registry. Made CI pipeline to integrate security assessment. With this CI pipeline being part of the build process, we can approve code use for production. Suppose an error occurs in the security assessment. In that case, it should fail the pipeline process so that the images that are vulnerable and not approved after the evaluation are not pushed to the image registry. 

Container Design Patterns for Kubernetes are essential for optimizing and improving the efficiency of your Kubernetes deployments. In this article, we will explore various design patterns that can help you make the most out of your containerized applications in a Kubernetes environment. Read the Article,Container Design Patterns for Kubernetes 

  • Vulnerability Scanning before Moving Deployments to Production

Organizations must check for vulnerabilities before moving the deployments to production. Otherwise, the migration of deployments to production increases the vulnerable workloads. Also, a healthy  DevOps/DevSecOps culture must be maintained in the organization to prevent these issues. 

  • Secure CI/CD Pipelines on Kubernetes

Make sure to have a CI/CD pipeline running on the built environment, which develops, tests, and deploys the workloads before using them in the Kubernetes cluster. Also, configuring CI/CD must report potential vulnerabilities to the developers quickly. Otherwise, if these potentially vulnerable images are pushed to the Kubernetes production cluster, attackers can exploit these vulnerabilities and gain access to the groups. Check code regularly, to avoid this problem, for code deployment configurations. 

  • Using Authorization Policies

The complexity arises when multiple devices and interconnected microservices are multiple users; this is a nightmare.Kubernetes offer several authorization methods. We should use Role-Based Access Control(commonly referred to as RBAC) or Attribute-Based Access control (ABAC), ensuring that no user has more permission than they need to accomplish their task. 

  • Create Network Segmentation between Containers

If we run different applications on one Kubernetes cluster, there is a considerable risk that if one of the forms is compromised, the other becomes an easy target. Network segmentation can be the solution to this problem, as it ensures secure communication between containers. But the task of creating network segmentation between containers is not an easy task because of the 'dynamic' nature of the container IPs. Use Network firewalls to prevent cross-cluster communication if necessary. 

Implement Spinnaker with Kubernetesto streamline and automate the deployment process. By leveraging Spinnaker's capabilities, organizations can achieve faster and more reliable deployments in their Kubernetes clusters. 

Kubernetes Security Tools 

Kubernetes automates various tasks required to deploy containerized apps. But one crucial thing that it doesn't take care of is SecuritySecurity. It does have a few features that can surely help to secure the containerized apps. But that is not much.  When properly configured, it can enforce role-based access control policies, for example, and it can restrict the ability of a container to access resources on the host server. 

Beyond these security measures, however, Kubernetes offer nothing in the securing of applications. It doesn't review the contents of a container for security flaws or detect anomalous behavior within a containerized app that could signal a breach. It doesn't secure nodes or harden networks against attack. In short, Kubernetes is a container orchestration tool. It's not a security tool. But Thankfully, we have third-party tools that can help us with security. 

 

1. Project Calico

Project Calico is an open-source tool that connects and secures containers and the services it runs. Integrate all the major cloud platforms with Calico, be it Kubernetes or OpenStack.

 

2. Kube-Bench

The Center for Internet Security (CIS) offers guidance and evaluation checks to insure the application is safe.  Kube-Bench is an open-source Kubernetes testing application that verifies that the Kubernetes implementation follows CIS standards. It supports benchmark testing of several Kubernetes versions. Kube-Bench is an application from Go.

 

3. Twistlock

Twistlock is a provider of full-lifecycle container and cloud-native security solutions. It helps you to perform over 200 built-in checks for the Kubernetes CIS Benchmarks. Twistlock defends software through the product life cycle with actionable risk detection mechanisms and dynamically configured firewalls.

 

4. Falco

Falco is a targeted Kubernetes tool for SecuritySecurity that detects unusual activity in your containers. Derive it from the Sysdig Project and has become a commercial product. Falco monitors containers with a greater focus on kernel system calls.

 

5. Aqua Security 

Until deployment Aqua Security scans the container images, this feature lets you make images read-only. Immutable images are less vulnerable to threat. Additionally, it allows quick detection of anomalies. 

Next-gen cyber security encircles a holistic approach—right from detection to protection, prevention, and remediation.Kubernetes Security Consulting Services 

Kubernetes Security and the Future  

The emergence of Kubernetes and containers hasn't modified the security goals. The aim is still to make it impossible, for cyberattackers to hack into the software and the networks and find and avoid them as soon as possible should they succeed. However, XenonStack being a Kubernetes Certified Service Provider can tailor the methods and methodologies to fit the requirements of DevOps operations and cloud-native concepts.