What is Kubernetes Vulnerability Scanning?

Containers gained popularity in the 2010s because they allowed developers to run programs across environments, but deploying thousands of them could be chaotic. Enter Kubernetes, an orchestration platform that emerged to manage containers at scale. But Kubernetes itself, not just its containers, needs vulnerability scanning. How? What should that look like? From merging tools to spanning the development lifecycle as well as the Kubernetes environment and the containers it contains, we’re breaking it down.

What is Kubernetes Vulnerability Scanning?

Kubernetes vulnerability scanning is a security tactic that scrutinizes the Kubernetes environment, including:

• Cluster configuration: Checking for Kubernetes settings, permissions, and exposed services
• Kubernetes components: Scanning critical Kubernetes components like the control plane, API server, and etcd database
• Container images: Inspecting container images stored in registries or running in the cluster for outdated dependencies, vulnerabilities, and insecure libraries. 

Kubernetes automated container scaling, deployment, and recovery — everything from updates to ensuring containers can always communicate with each other and users can always connect to a working container — so today, companies build and run apps faster and easier. 

But the managerial powers of Kubernetes that give it control over how containers are deployed also present a new attack surface. And if attackers compromise Kubernetes itself, they can control the entire container environment.

While Kubernetes vulnerability scanning might suggest scanning at the level of orchestration for setup problems only, scanning containers themselves can be part of the discussion on Kubernetes vulnerability scanning. On the other hand, Kubernetes runtime security focuses on watching for live threats, whereas the broader Kubernetes security includes the tactics and strategies used to secure everything from the setup to live threat defense.

The Full Scope of K8s Vulnerabilities

A vulnerability is a weakness or flaw in a system that attackers can exploit. In the context of Kubernetes, vulnerabilities can occur at various levels — from container images to Kubernetes’ core components like its control plane, nodes, and networking services. Publicly disclosed vulnerabilities are numbered and cataloged as CVEs (common vulnerabilities and exposures).

More of these flaws are identified and exploited all the time. That means organizations and vendors aren’t even currently aware of all the flaws in their systems. Vulnerabilities often come to light after a security incident, so identifying and re-engineering thousands of containers to accommodate new patches for new vulnerabilities, across thousands of instances, continually, is no simple task.

To secure Kubernetes effectively, it helps to understand its most common vulnerability categories, including:

Container Image Risks 

Container images vulnerabilities are an outsized category of flaws impacting Kubernetes. DevOps teams often use open-source components to build their container images, which is an inherently risky process because these images don’t necessarily follow best practices, so it’s easy for vulnerabilities to proliferate.

Configuration Weaknesses 

Kubernetes is a powerful solution. One appeal is that it can be customized in multiple ways. This customization makes it very easy to misconfigure the environment, whether through improper access settings or open API endpoints. Any issues in configuration means that the environment is at risk. 

Runtime Threats  

Security vulnerabilities at runtime are some of the most difficult to uncover with scanning solutions. Traditionally, container images are scanned for vulnerabilities prior to deployment. This means issues that don’t emerge until the execution phase – like container escapes or lateral movements – are often left undetected. 

Being able to detect and resolve these issues quickly can improve the security of the entire environment. 

Infrastructure Vulnerabilities 

The underlying infrastructure that supports Kubernetes can be a point of weakness in the system. This could be the cloud platform on which Kubernetes is deployed or the bare-metal server used for a self-hosted environment. For example, if Kubernetes worker nodes are configured with default credentials and exposed to the public internet, attackers can gain access to the underlying servers.

Organizations must ensure that the infrastructure layer is properly secured by restricting access, applying patches, and monitoring cloud provider configurations for any drift or vulnerabilities.

Supply Chain Concerns 

Open-source applications tied into Kubernetes to extend the capabilities of the platform can create new risks. Organizations can use open-source vulnerability management solutions to track any possible software supply chain issues within their Kubernetes environments. They can also employ more comprehensive platforms like cloud-native application protection platforms (CNAPPs) to identify supply chain issues across clouds, explore their unique contingencies and versions, and build remediation into their CI/CD lifecycles.

Visibility into the supply chain is a core concern in a Kubernetes environment.

Overcoming Common Scanning Challenges

Kubernetes vulnerability scanning, while key to maintaining a secure environment across all categories of vulnerabilities, comes with its own set of challenges. Those difficulties ultimately complicate team efforts to scan all the categories and lifecycle stages that secure Kubernetes. 

What do those look like? Here’s a primer:

Challenge	What it Means	How to Solve It
Performance issues	Kubernetes scanning may slow down deployments if scans are resource-intensive.	Use pipeline-integrated scanning to minimize delays and scan critical workloads first.
False positives	Inaccurately tuned scans can generate false positives, overwhelming teams.	Use context-aware tools that consider Kubernetes-specific configurations.
Scale management	Scanning large environments with thousands of containers can take too long.	Automate CI/CD-integrated scanning to check containers before deployment.
Gaps in coverage	Vulnerability scanners may miss environments if clusters or namespaces are unknown.	Gain multi-cluster and multi-cloud visibility and automatic environment discovery.
Resource constraints	Scanners may be allocated too few resources, reducing scan depth or causing failures.	Use autoscaling scanners that dynamically adjust based on load.
Dynamic workloads	Containers are constantly created, updated, and deleted, creating blind spots.	Use real-time runtime monitoring to scan containers during operation.
Configuration complexity	Misconfigurations can result in security gaps, even with scanned containers.	Use security-as-code practices like policy-based scanning.

Runtime-powered CNAPPs with shift-left capabilities address many of the hurdles in Kubernetes scanning by automating vulnerability detection, improving scalability, and reducing false positives through context-aware scanning. By integrating directly into CI/CD pipelines, they can also automate scans before deployment, minimizing performance slowdowns while ensuring vulnerabilities are detected early. 

This kind of coverage goes beyond traditional IaC scanning, which works statically to scan files for misconfigurations without runtime context. Instead, look for solutions that combine runtime context (like open ports, active workloads, and API endpoints) with pre-deployment scanning. 

Scanning Across the Application Lifecycle

Remember, truly effective Kubernetes vulnerability scanning doesn’t need to cover just the challenges of workload complexity or bottlenecks; it needs to address these challenges at every stage of the lifecycle. 

After all, each stage of the lifestyle, along with each type of vulnerability, introduces its own risks and requires its own scanning capabilities to mitigate issues. Let’s recap what that looks like:

1. Build-Time Security Checks

The foundation of Kubernetes security starts with build-time checks on container images. Scanning container images during development helps teams catch issues like outdated dependencies, critical vulnerabilities, and misconfigurations early.

For instance, a container image with a known CVE in its operating system base layer should trigger an alert and block deployment until patched. Tools like a CNAPP’s CI/CD integration can automate this process.

Paying attention to build-time scanning solves correlated scanning challenges, too:

• Performance issues: Scanning within the CI/CD pipeline prevents bottlenecks by scanning before deployment
• False positives: Even without advanced behavioral analysis, accurate tuning can help avoid excessive alerts during builds
• Scale management: Scanning images one by one during the build process minimizes overwhelming scans at later stages

2. Deployment Validation

Validation during deployment means that containers entering production meet strict security standards. That includes enforcing registry protection policies, verifying that containers are sourced from trusted repositories, and resolving critical vulnerabilities before deployment.

Here’s an example: Kubernetes admission controllers may block pods with unscanned or vulnerable container images. Policy enforcement tools make sure unauthorized workloads aren’t deployed.

Attention at this phase solves for the following scanning challenges:

• Gaps in coverage: Deployment validation means unknown workloads don’t slip through
• Resource constraints: Proper policy enforcement prevents wasting compute resources on unapproved workloads
• Configuration complexity: Automated policy enforcement streamlines complex deployments with interacting services

3. Runtime Monitoring

Some vulnerabilities only emerge at runtime, making real-time monitoring after deployment a must. That’s where runtime monitoring comes in, detecting issues like unexpected process executions, network anomalies, and privilege escalations that static scans miss.

For instance, if a compromised container tries to access restricted Kubernetes services through an unauthorized API call, runtime threat detection tools can block or quarantine the affected pod automatically.

Focusing on runtime helps teams solve scanning challenges like:

• Dynamic Workloads: New or updated containers deployed automatically can be tracked at runtime.
• False Positives: Context-aware monitoring reduces alert fatigue by focusing on real threats, not hypothetical risks.
• Scale Management: Automated scaling includes continuous runtime monitoring, even across thousands of workloads.

 4. Continuous Assessment and Remediation

Security isn’t a one-time task — code updates, configuration changes, and zero-day threats emerge all the time. Continuous vulnerability scanning helps detect new vulnerabilities early so clusters stay secure even as workloads evolve.

Ongoing visibility into the cluster’s security posture reduces the risk of undetected breaches.

The scanning challenges solved at this stage are:

• Gaps in Coverage: Automated discovery tools continuously assess new clusters, nodes, and deployments so they’re always on the radar.
• Resource Constraints: Autoscaling scanners make sure that as workloads grow, scanning resources grow, too.
• Configuration Complexity: Regular policy reassessments catch evolving misconfigurations that might not exist at deployment.

Skipping any stage in the application lifecycle increases the attack surface and leaves Kubernetes environments exposed, so Kubernetes vulnerability scanning must handle not just all the categories of vulnerabilities, but the stages of the development lifecycle, too. 

Upwind Solves for Kubernetes Vulnerability Scanning

Upwind’s real-time vulnerability detection across multi-cloud and multi-architecture environments helps security teams automatically detect and prioritize the vulnerabilities that pose the biggest risks. With runtime intelligence, Upwind precisely identifies critical risks and enables focused, efficient, and intelligent security. And with integration into the CI/CD lifecycle, Upwind shifts left to cover built-time vulnerability remediation as well.

To learn more about Upwind’s vulnerability management solution, request a demo today.

Frequently Asked Questions

How often should Kubernetes environments be scanned?

According to security best practices, Kubernetes environments should be scanned for vulnerabilities at least daily, ideally as part of your continuous integration and continuous deployment (CI/CD) pipeline, to catch potential security issues early in the development cycle and ensure timely remediation. Scanning should include container images, configurations, and cluster components. 

What’s the difference between image and runtime scanning?

Not all Kubernetes scanning includes containers. Image scanning involves inspecting the container image itself during build-time for any potential vulnerabilities. But that won’t help teams identify problems in the Kubernetes environment.

Runtime scanning involves identifying vulnerabilities in containers and processes in the live environment. Scanning focuses on real-time attacks, anomalies, and system behavior rather than for known vulnerabilities.

How do you handle scanning in multi-cluster environments?

Kubernetes clusters include the control plane, nodes, pods, networking, and storage: in other words, they encompass workloads, machines that run containers, and the systems managing that workload.

Adopting an event-driven approach to multi-cluster environments means adopting centralized management to apply consistent security policies, automate scanning across clusters, and aggregate findings in a single dashboard. Runtime monitoring tools and runtime-powered CNAPPs are key, since teams who manage multi-cluster environments will need to automatically discover new workloads, enforce policies, and continuously monitor those clusters for vulnerabilities and threats.

What role do vulnerability scanners play in compliance?

Vulnerability scanners play a critical role in compliance. Here are the core ways they help:

• Risk Identification: They detect security vulnerabilities, misconfigurations, and policy violations across containers, infrastructure, and applications.
• Compliance Checks: Vulnerability scanning is a required part of meeting compliance requirements in regulatory frameworks like PCI-DSS, GDPR, HIPAA, SOC 2, ISO 27001, and CIS Benchmarks.
• Audit Readiness: They generate detailed compliance reports for audits, showing scan results, remediation actions, and policy enforcement.
• Continuous Monitoring: They provide real-time scanning to maintain compliance even as new vulnerabilities emerge.
• Policy Enforcement: Scanners can apply security policies automatically to ensure that workloads meet compliance standards before deployment.
• Remediation Tracking: Scanners track vulnerability fixes and patch updates so violations get fixed quickly.

How do you prioritize vulnerability remediation in Kubernetes?

There are multiple ways to tackle vulnerability prioritization. Organizations can use:

• Common Vulnerability Scoring System (CVSS) scores 
• Insight into exploitability
• Business impact
• Exposure in the Kubernetes context
• Criticality given runtime context
• Compliance requirements

Ultimately, filtering the criticality of vulnerabilities is a multifaceted job. Combining known vulnerability risks with the runtime environment is key to taming the alert overload and addressing truly critical vulnerabilities first.