The top 11 open-source Kubernetes security tools

Kubernetes security: A refresher

As its adoption surges, more organizations are turning their attention to Kubernetes security, working to fortify their clusters against potential threats. It’s a good instinct. The open-source nature of Kubernetes makes it a lucrative target for attackers aiming to exploit vulnerabilities to breach systems. A secure Kubernetes environment ensures the confidentiality, integrity, and availability of applications, safeguarding business assets and data from unauthorized access. Before turning to an action plan for a robust Kubernetes environment, let’s start by taking a look at some common risks, critical components to secure, and challenges.

Common vulnerabilities and threats in Kubernetes environments

Kubernetes threat vectors target multiple layers of your containerized infrastructure, creating complex attack paths that traditional security measures often miss.

The most critical threats include:

• API server vulnerabilities: Misconfigured or exposed APIs provide direct access to cluster management functions, allowing attackers to manipulate workloads and extract sensitive data.

• Container image risks: Vulnerable base images or malicious code within containers create entry points for attackers to compromise entire clusters.

• Configuration weaknesses: Default settings and misconfigurations in network policies, RBAC, or secrets management leave clusters exposed to privilege escalation and lateral movement attacks.

Understanding these vulnerabilities is just the first step. It's equally important to know which components need safeguarding to mitigate these risks. This is where Kubernetes security testing tools play a crucial role, helping organizations identify and address potential vulnerabilities before they can be exploited.

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Components and domains to secure in Kubernetes

Kubernetes security domains require protection at multiple infrastructure layers to prevent attackers from exploiting any single point of failure.

• Control plane security: The API server acts as the primary gateway to your cluster and requires strict authentication, authorization policies, and audit logging to prevent unauthorized access.

• Data protection: etcd stores all cluster configuration data and secrets, making encryption at rest and secure communication protocols essential to prevent data breaches.

• Node hardening: Worker nodes and kubelet agents need secure configurations, regular updates, and restricted access to prevent compromise of the underlying infrastructure.

• Network isolation: Pod-to-pod communication must be controlled through network policies to prevent lateral movement and unauthorized data access between workloads.

• Workload permissions: Applications should operate under the principle of least privilege, with minimal permissions and restricted access to sensitive resources.

• Secrets management: Sensitive data like passwords, tokens, and certificates require encryption, access controls, and rotation policies to prevent credential theft. The widespread exposure of secrets—affecting 61% of organizations according to Wiz's Code Security Report—makes proper secrets management particularly critical in Kubernetes environments.

Challenges in Kubernetes security

Securing a Kubernetes environment is no easy task. There are many challenges, including:

• Misconfigurations: Simple errors in configuration can open up significant vulnerabilities.

• Inadequate network policies: Lax network policies can allow unauthorized access to network resources.

• Lack of resource isolation: Failure to isolate resources can result in cross-contamination and data breaches.

• Insufficient monitoring and logging: Detecting and responding to threats becomes increasingly more complicated without proper monitoring.

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How security tools can help

Kubernetes security tools address the complexity and scale challenges that manual security processes cannot handle effectively in dynamic containerized environments.

• Automated vulnerability detection continuously scans containers, configurations, and runtime environments to identify security gaps before attackers can exploit them, reducing response time from days to minutes.

• Policy-as-code enforcement ensures consistent security standards across all clusters and deployments, preventing misconfigurations that lead to breaches.

• Runtime threat monitoring detects suspicious activities like privilege escalation, lateral movement, and unauthorized access in real-time, enabling immediate response to active threats.

• Compliance automation maintains adherence to security frameworks like CIS benchmarks, SOC 2, and industry regulations without manual audit overhead.

Key features to look for in Kubernetes security tools

Choosing the right Kubernetes security tools can be overwhelming. Here are the key features to look for when evaluating your options:

• Comprehensive coverage: The best tools protect every layer of your Kubernetes environment—configuration, workloads, network, runtime, and policy enforcement.

• Open source and community support: Look for tools with active communities, frequent updates, and transparent development. This ensures you get timely fixes and new features.

• Easy integration: Tools should fit into your existing workflows, whether that's CI/CD pipelines, GitOps, or your preferred monitoring stack. Command-line interfaces, APIs, and plug-ins are a plus.

• Automated scanning and policy enforcement: Automation is key. Tools should scan for misconfigurations, vulnerabilities, and compliance issues automatically, and enforce policies without manual intervention.

• Real-time detection and alerting: Runtime security tools should monitor for suspicious activity and alert you instantly, so you can respond before issues escalate.

• Customizability: Every environment is different. Choose tools that let you write custom rules, policies, or checks to match your organization's needs.

• Clear reporting and actionable insights: The best tools don't just find problems—they help you understand what to fix first, and how to fix it.

• Scalability: Make sure your tools can handle your current and future cluster sizes, whether you're running a handful of nodes or hundreds.

Before you commit, try out a few tools in a test environment. See how they fit your workflow and how easy they are to use. The right combination will make your Kubernetes security program much more effective—and a lot less stressful.

Kubernetes security tools

Open-source Kubernetes security tools provide enterprise-grade protection without licensing costs, offering transparency and customization that proprietary solutions often lack. These tools address specific security domains—from configuration scanning to runtime protection—allowing you to build a comprehensive defense strategy tailored to your environment's needs.

The following tools are organized by security function to help you identify the right combination for your cluster's protection requirements.

Configuration and compliance scanners

Configuration scanners analyze Kubernetes YAML files, Helm charts, and cluster settings to identify security misconfigurations before deployment. These tools compare your configurations against security benchmarks like CIS Kubernetes Benchmark and industry best practices, flagging issues like excessive permissions, unencrypted secrets, or exposed services that could lead to breaches.

kube-bench

kube-bench is an open-source tool that verifies the secure deployment of Kubernetes based on the CIS Kubernetes Benchmark guidelines. With its YAML-configured tests, updating the tool as standards change is straightforward:

Use cases

Checkov

Checkov is a static code analysis tool built by Bridgecrew and maintained by Prisma Cloud. It scans cloud infrastructure configurations to identify security misconfigurations before deployment. Checkov supports a wide range of infrastructure as code (IaC) languages, including Terraform, CloudFormation, and Kubernetes YAML files. And it comes with built-in policies that adhere to best practices and lets you write custom policies in Python or YAML.

# Installing Checkov using pip
pip install checkov

# Running a Checkov scan on a specific file
checkov -f main.tf

# Running a Checkov scan on a directory
checkov --directory /user/path/to/iac/code

# Specifying a framework to scan (e.g., terraform, cloudformation, kubernetes)
checkov --framework kubernetes

Use cases

Terrascan

Terrascan is a tool that scans infrastructure as code (IaC) for potential issues. It checks for misconfigurations in IaC and keeps an eye on cloud setups for any changes that might weaken security. Before you set up cloud-native systems, Terrascan helps catch and fix security gaps and compliance breaches. You can use it on its own or add it to your CI/CD process. It works with many IaC languages, like Terraform, Kubernetes, and Dockerfile, and it’s compatible with cloud giants like AWS, Azure, and GCP.

Use cases

KubeLinter

KubeLinter is an open-source command-line tool that spots misconfigurations in Kubernetes objects. It reviews Kubernetes YAML files and Helm charts before they're deployed to a cluster. With 19 default checks and the option to add your own, KubeLinter quickly alerts you to any missteps or security breaches in Kubernetes. Developed using Go, KubeLinter requires minimal configuration and is easy to use in various command-line shells.

# Installing KubeLinter using Homebrew
brew install kube-linter

# Linting a single Kubernetes YAML file
kube-linter lint path/to/yaml-file.yaml

# Linting an entire directory and its subcontents
kube-linter lint path/to/directory/containing/yaml-files/

# Linting a Helm chart
kube-linter lint path/to/directory/containing/Chart.yaml-file/

Use cases

Runtime security and threat detection tools

Runtime security tools monitor active Kubernetes workloads for malicious behavior that static scanning cannot detect. Unlike pre-deployment scanners, these tools observe actual container execution, system calls, and network activity to identify threats like privilege escalation, container escape attempts, and unauthorized file modifications as they occur in production environments.

Falco

Falco is a cloud-native runtime security project initially created by Sysdig and now maintained by the Cloud Native Computing Foundation (CNCF). It leverages system calls at the kernel level to monitor the runtime behavior of a system, integrating metadata from container runtime and Kubernetes to clarify what's happening. Falco can detect abnormal behavior and potential security threats in real time, offering a powerful rules engine to assert the stream of syscalls and alert users when rules are violated.

Use cases

Trivy

Trivy is an open-source, all-in-one scanner for containers and Kubernetes that identifies vulnerabilities and misconfigurations across images, file systems, and cluster resources. It supports Kubernetes cluster and manifest scanning—including exposed secrets and policy issues—and integrates into CI/CD to stop risky workloads before deployment. Trivy offers multiple scanning modes—from image and repository scans to cluster-wide audits—providing a comprehensive view of your Kubernetes security posture.

# Installing Trivy
brew install trivy

# Scanning a container image
trivy image nginx:latest

# Scanning a Kubernetes cluster
trivy k8s --report summary cluster

# Scanning IaC files
trivy config ./kubernetes-manifests/

Use cases

Policy management and enforcement

Policy enforcement engines automatically validate Kubernetes resources against predefined security rules before they're deployed to your cluster. These tools act as admission controllers, blocking deployments that violate security policies—such as containers running as root, missing resource limits, or prohibited image registries—ensuring only compliant workloads enter your environment.

Open Policy Agent (OPA)

Open Policy Agent (OPA) is an open-source, versatile policy engine that streamlines policy application across different areas, such as microservices, Kubernetes, CI/CD processes, and API gateways. OPA allows you to specify policies as code using Rego. It can also easily connect with your software, making policy decisions based on various data inputs.This flexibility makes it a powerful tool for policy enforcement in a wide range of applications.

Use cases

kubeaudit

kubeaudit helps you audit Kubernetes clusters for various security concerns, including the detection of misconfigurations and non-compliance with best practices. It's tailored for Red Hat OpenShift and can scan user code for recognized mismatches, assisting in resolving them before integrating the code into OpenShift. A static analyzer that is easy to use and extend, kubeaudit also offers a platform for community contributions to enhance its auditing capabilities.

# Example audit report of a YAML file with kubeaudit
$ kubeaudit all -f "deployment--v1.yml"

---------------- Results for ---------------

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: deployment
    namespace: deployment-v1

--------------------------------------------
...
-- [error] AutomountServiceAccountTokenTrueAndDefaultSA
   Message: Default service account with token mounted. automountServiceAccountToken should be set to 'false' or a non-default service account should be used.

-- [error] CapabilityShouldDropAll
   Message: Capability not set to ALL. Ideally, you should drop ALL capabilities and add the specific ones you need to the add list.
   Metadata:
      Container: container
      Capability: AUDIT_WRITE
...

Use cases

Network security and service mesh

Network security and service mesh tools provide network policies, segmentation, and service mesh capabilities to secure communications within Kubernetes. This is critical because, according to NSA and CISA guidance, Kubernetes applies no network policies by default, resulting in unrestricted traffic within the Pod network. These tools play a crucial role in preventing unauthorized access and ensuring data integrity during transmission.

Calico

Calico is an open-source networking solution and network policy engine for containers. It operates at layer 3 of the networking stack, providing both networking and network policy for Kubernetes. The tool uses the Border Gateway Protocol (BGP) to handle packet routing to pods. Calico can be used as a standalone tool or in conjunction with others, like Flannel.

Calico also extends the features of the built-in Kubernetes NetworkPolicy API, allowing you to apply policies to a broader range of objects and offering more granular control over traffic flow in your Kubernetes environment.

# Example of allowing ingress traffic to endpoints in the production namespace with database label is permitted, only if it comes from a pod in the same namespace with backend label, on port 6379
apiVersion: projectcalico.org/v3
kind: NetworkPolicy
metadata:
  name: allow-tcp-6379
  namespace: production
spec:
  selector: app == 'database'
  ingress:
    - action: Allow
      protocol: TCP
      source:
        selector: app == 'backend'
      destination:
        ports:
          - 6379

Use cases

Istio

Istio is an open-source service mesh designed for Kubernetes, facilitating the connection, security, management, and monitoring of services. It boasts features like traffic control, security measures, monitoring options, and adaptability.

Istio deploys a sidecar proxy (Envoy) with each service instance, so it can intercept and manage all incoming and outgoing traffic. This architecture enables Istio to enforce policies, collect telemetry, and facilitate advanced traffic routing patterns like canary deployments and circuit breaking.

Use cases

Exploit detection

Exploit detection tools identify potential escape techniques and exploits in Kubernetes environments. By actively monitoring and analyzing system behaviors, these tools play a pivotal role in preventing unauthorized breaches and ensuring the overall security of the environment.

Kubescape

Kubescape, developed by ARMO, is a Kubernetes security platform that’s a Cloud Native Computing Foundation (CNCF) sandbox project. The platform facilitates risk analysis, security compliance, and misconfiguration scanning in Kubernetes environments. Kubescape can check clusters, YAML files, and Helm charts, detecting misconfigurations using frameworks including NSA/CISA, MITRE ATT&CK®, and the CIS Benchmarks.

Use cases

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This guide breaks down the key capabilities to look for in a Kubernetes security platform and how to align them with business risk.

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Securing K8s across the entire development lifecycle

Securing Kubernetes (K8s) is a continuous process that spans the entire development lifecycle.

The importance of continuous security

Here’s why it’s critical to treat Kubernetes security as an ongoing priority, starting at the planning phase of your implementation:

• Early detection of vulnerabilities: Integrating security from the outset translates directly to the early detection of Kubernetes vulnerabilities, reducing potential risks in later stages of development.

• Cost-efficiency: Addressing security breaches post-deployment is an expensive process. Early security integrations are significantly more cost efficient.

• Compliance with regulations: Continuous security ensures that your system adheres to the necessary regulatory compliances at all stages of development. By constantly monitoring and updating in response to evolving standards, it guarantees that the system remains in line with industry regulations. This proactive approach reduces the risk of non-compliance penalties and ensures that security measures are always up to date.

Risks of late-stage security implementations

• Increased complexity: The later the development stage, the more complex security implementation becomes. That’s because accumulated data and configurations come with a lot of baggage, like dependencies and interconnected system components.

• Potential security breaches: Late-stage security implementations mean your system has been vulnerable to attacks for an extended period.

• Reputational damage: Don’t wait for a security breach to prioritize security. Cyberattacks can damage an organization's reputation, leading to a loss of trust among clients and stakeholders.

Wiz's container and Kubernetes security solution

While the tools covered in this blog post cater to many different aspects of Kubernetes security, Wiz stands out as a single–platform solution that’s specifically tailored for container and Kubernetes environments. Wiz empowers both security and development teams by providing visibility, context, and risk prioritization throughout the entire development lifecycle.

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Some of its standout features include:

• Comprehensive security: Wiz offers a comprehensive security approach, covering all aspects of Kubernetes security to make sure you’re defended against potential threats.

• Ease of integration: With seamless integration into existing systems, Wiz provides complete security coverage without disrupting your existing workflows.

• Real-time monitoring: Wiz offers real-time monitoring of the entire Kubernetes environment, providing instant alerts for security breaches, so you can respond to threats fast.

Other tool roundups you might be interested in:

• 11 Native AWS Security Tools

• The best IaC tools [By use case]