Kubernetes security basics

What is Kubernetes security?

Kubernetes security is the application of techniques and processes to protect cloud-native applications running on Kubernetes (also known as K8s) from vulnerabilities or malicious actors.

Kubernetes is an open source container orchestration platform designed to enhance the scalability and reliability of cloud-native applications. Its powerful feature set and ease of integration make it the perfect choice for small startups looking to compete in the global market and for large enterprises like Spotify and Major League Baseball that need to serve a global audience.

However, unleashing the full potential of K8s requires relying on containers and microservices running in the cloud, which come with their own unique security considerations. Understanding common security issues in Kubernetes and overcoming their challenges is the first step toward strengthening your application's overall cloud security posture.

Common security issues in Kubernetes

A typical Kubernetes cluster consists of:

Control plane: This is the brain of the K8s group. It exposes the cluster to the Kubernetes API, schedules resource allocation and provisioning, and responds to events within the cluster. Nodes: This is where work is done within the K8s cluster, housing and processing data as required by the application. Nodes consist of smaller individual units that work in harmony.

These two elements of the Kubernetes cluster make up a large portion of the total Kubernetes attack surface. The application itself can introduce additional security vulnerabilities through faulty code and outdated libraries. Additionally, the flexibility of a Kubernetes host makes it a potential attack surface.

For example, if an organization deploys a Kubernetes cluster on the public cloud, it should be aware of any potential security vulnerabilities known to the platform and restrict access to the cluster as much as possible.

Understanding where these threats come from is vital to enhancing Kubernetes security. According to the CrowdStrike 2024 Global Threat Report, there was a 75% increase in cloud breaches in 2023, forcing companies to adapt their security posture to address this growing threat.

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Common security issues in Kubernetes include the following, and should be addressed along with other common cloud vulnerabilities:

Misconfigurations that throw security settings out of alignment or unintentionally expose sensitive information Insecure or unauthorized containers Unauthorized access to the Kubernetes dashboard Unauthorized access to API requests or network ports Incorrect configuration of external tools Improper identity and access management policies The correct one

Kubernetes security incidents

Failure to properly secure K8s clusters and surrounding infrastructure can have serious consequences on application data and operating revenue. Here are some notable examples of recent Kubernetes security breaches.

February 2018: Hackers accessed the insecure Kubernetes management console in the automaker's cloud accounts. Once they gained access, they installed malware to start mining cryptocurrencies within its infrastructure. The hack also exposed sensitive telemetry data. July 2019: A firewall misconfiguration exposed a financial institution's K8 pools to the public internet, triggering a breach that resulted in the theft of 30GB of credit application data. August 2023: Researchers discovered that K8 groups belonging to more than 350 organizations were not secure and publicly accessible due to two configuration errors. The list of organizations included large companies listed on the Fortune 500 list, in addition to small companies and individual projects. January 2024: Researchers find that a misunderstanding of user access permission sets within Google Kubernetes Engine creates a vulnerability that potentially exposes millions of containers to any user with a Google account. A Nasdaq-listed company was named as one of the organizations that experienced this misconfiguration.

Basics of security posture management in Kubernetes

Developers must consider the entire Kubernetes lifecycle when trying to strengthen the security posture of cloud-native applications. There are two main areas to consider:

Before a Kubernetes cluster: Since Kubernetes relies on container images, you must ensure that containers are secure before they enter the cluster. Making image scanning part of your Continuous Integration/Continuous Delivery (CI/CD) pipeline ensures containers are properly configured and updated with the latest security patches and will not introduce malware or other vulnerabilities into the K8s cluster. Within a Kubernetes cluster: Many areas within the cluster must be secured to mitigate the risk of malicious activity or inadvertent data exposure. Control Plane: Control plane resources are stored in etc, so access to etc should only be available via the Kubernetes API with appropriate permissions. Kubernetes API: The API is the method that external users will use to access the control plane, so restricting access to authorized users is vital. Use OpenID Connect (OIDC) providers to secure access to the K8s cluster and use Role-Based Access Control (RBAC) to set access control specifications for each Kubernetes object and namespace. You can also use Kubernetes admission controllers to monitor and regulate requests directed to the Kubernetes API server to ensure that unauthorized API calls do not reach your K8s cluster. Networking: Configuring network policies will allow Kubernetes to create firewalls that protect unauthorized access or data transfer between pods. Nodes: Kubelets send communications between the control plane and the container engine running the workload within the nodes. Effectively securing a kubelet requires configuring and monitoring the communication between the Kubernetes API and the kubelet and the communication between the kubelet and the container engine. Container and Runtime: Vulnerabilities such as misconfigurations, zero-day exploits, privilege escalation, and malware can appear in deployed containers. Implementing Kubernetes security tools like CrowdStrike Falcon® Cloud Security ensures that all aspects of the container are monitored and secured during deployment.

In addition to securing the K8 lifecycle, collecting and maintaining Kubernetes logs will allow you to troubleshoot performance bottlenecks, identify vulnerabilities, and investigate breaches if they occur. Using CrowdStrike® Falcon Next-Gen SIEM will dramatically improve visibility into your Kubernetes clusters and enhance your ability to respond to incidents.

Kubernetes security tools

Some of the most popular Kubernetes security tools include:

Platform/Tool Description Falcon Cloud Security Falcon Cloud Security provides comprehensive security capabilities for Kubernetes environments, helping organizations protect their workloads, effectively detect and respond to threats, and maintain compliance with regulatory requirements. FalcoFalco is an open source Kubernetes security tool originally designed by Sysdig to detect anomalous behavior in containerized applications. It uses runtime and system call metrics to identify potential security threats, providing real-time alerts and visibility into Kubernetes clusters. Falcon SidekickFalco Sidekick is an open source companion tool for Falco that extends its capabilities in handling alerts and notifications. It integrates with various communication channels, such as Slack and email, to provide real-time alerts and notifications of security events detected by Falco. The Kubernetes CIS BenchmarjCIS provides guidelines for securing Kubernetes deployments. Many open source tools, such as kube-bench, can automate the evaluation of Kubernetes clusters against these criteria, helping to ensure compliance and adherence to security best practices. Kube-hunterKube-hunter is an open source penetration testing tool designed specifically for Kubernetes environments. It identifies potential vulnerabilities and misconfigurations within Kubernetes clusters, helping organizations proactively address security risks. Kube-BenchKube-bench is an open source tool that checks Kubernetes deployments against the CIS Kubernetes Benchmark. It automates the performance testing process, providing organizations with insights into potential security misconfigurations and areas for improvement. KyvernoKyverno is an open source Kubernetes native policy engine used to enforce security policies and best practices. It allows organizations to define and enforce policies across Kubernetes resources, ensuring compliance, security, and operational consistency within the cluster. OPA/GatekeeperOpen Policy Agent (OPA) with Gatekeeper is an open source policy execution engine for Kubernetes. It enables organizations to define and enforce policies for resource configurations and access control, ensuring compliance and security across Kubernetes deployments.

How CrowdStrike can help

Kubernetes offers scalability and powerful processing capabilities, but its complexity brings many challenges to improving security. Even a simple misconfiguration can inadvertently expose sensitive data to the public, so developers must monitor all aspects of the K8 lifecycle for potential vulnerabilities.

Kubernetes is also a very flexible platform, allowing for third-party integration with tools that will strengthen your security posture with automated scanning and alerting mechanisms. Integrating Kubernetes security tools that work alongside your K8 workloads is critical for maximum security.

CrowdStrike Falcon® Cloud Security delivers container, Kubernetes, and host protection from creation to runtime in AWS, Azure, and Google Cloud while ensuring security at every step of the CI/CD pipeline.