Kubernetes is the fastest-growing open-source project and the go-to cluster management solution due to its scalability, flexibility, and efficient resource management.

In the past 2 years, 60% of organizations have started using Kubernetes, and many more are considering it. However, a Red Hat report shows that security problems have led 67% of companies to delay or slow down their application launches.

Why? Because most businesses are too busy focusing on proof-of-concept work and testing, leaving security on the back burner.

When a company starts taking security measures, it’s too late and the business already suffers. 

A recent survey found that 46% of companies experienced significant impacts from security issues, resulting in either revenue loss or customer attrition.

How do you secure your infrastructure? 

Knowledge. A company that understands the most common security risks, how to solve them, and follows best practices can effectively safeguard its Kubernetes environment. 

In this blog, I will discuss common security challenges in Kubernetes, ways to address them, best practices, and a lot more.

1. Top 5 Most Common Kubernetes Vulnerabilities in 2024

Here are the top five most common vulnerabilities organizations need to be aware of:

Misconfigurations

Misconfigurations are often called Kubernetes’ “Achilles’ heel” because they are the most dangerous, single weak point that can bring down an otherwise secure and robust system.

Let’s take the 2018 Tesla cryptojacking attack for example. 

Tesla’s Kubernetes console was left open without password protection, and a simple misconfiguration exposed their AWS credentials. Attackers exploited this vulnerability, not to steal data, but to hijack computing resources for cryptocurrency mining. 

This cryptojacking incident highlights how a single oversight can lead to serious consequences, even in companies like Tesla which take security quite seriously.

Rory McCune, chief security consultant at NCC Group, says, 
“Kubernetes is very complicated, and it’s very easy to make a mistake on how you configure it.”

Simple misconfigurations like exposing the API server without proper authentication, using insecure container images, or not isolating workloads can have serious consequences.

Pro Tip:

Avoid using default settings, as they are often insecure. To avoid misconfigurations, secure your API server with strong authentication and access controls. Use RBAC to limit privileges. Refer to the CIS Benchmarks for guidance on hardening your setup. 

2.   Data Transmission and Access to etcd in Kubernetes

While most businesses focus on container security they often overlook data transmission security. A vulnerability in an unencrypted network allows attackers to intercept data and manipulate it in transit, compromising the entire cluster. 

One of the main targets of these attackers is gaining write access to etcd which stores all crucial states and secrets. Access to etcd is like having root access to the entire cluster.  If attackers exploit this, they can bypass security controls and escalate their privileges. 

Always implement Transport Layer Security (TLS) for all communications within your Kubernetes cluster. This ensures data is protected during transmission. 

Additionally, restrict access to etcd so only trusted components can connect. Use strong authentication methods, like mutual TLS, to secure these connections. Regularly review access controls to keep your environment safe from potential threats.

3. Vulnerable Third-Party Dependencies

Kubernetes ecosystems often rely on third-party components, including libraries, plugins, and container images. 

These dependencies are like a double-edged sword. While they enhance functionality, they also introduce potential vulnerabilities that attackers can easily exploit. 

As a report by Snyk suggests 78% of overall security vulnerabilities due to third-party dependency are indirect. These indirect dependencies are requested by the primary libraries or images you explicitly define in your manifests. 

Vulnerabilities in third-party dependencies can significantly threaten Kubernetes security in two ways: 

• Introducing new attack surface: Each third-party component introduces new code and functionality that may contain vulnerabilities. Attackers are on the hunt for these surfaces to exploit. 
• Supply Chain Attacks: Attackers target popular libraries or container images to inject malicious code. When enterprises use these compromised dependencies, they inadvertently deploy insecure code, potentially leading to data breaches or system compromises.

Regularly update your Kubernetes cluster to the latest stable version to benefit from bug fixes and security patches. Additionally, monitor vulnerability databases and scan your container images and libraries to keep them up to date.

4. Denial-of-Service (DoS) Attacks

DDoS (Distributed Denial of Service) attacks are a major threat to online services. They work by flooding an application with too much traffic, making it unavailable to users. 

In a Kubernetes environment, these attacks can be especially harmful. When services are exposed to the internet, attackers can flood them with requests.

One dangerous type of attack is the “Yo-yo attack.” This happens when user activity spikes, causing Kubernetes to automatically scale up resources like pods and CPU. 

Attackers take advantage of this by sending fake requests. As a result, businesses face rising costs from unnecessary scaling, but they don’t see any real revenue.

To protect against DDoS attacks, implement rate limiting on your services. This controls the number of requests an application can handle – for example, 500 requests a minute or 5 requests a second. 

Moreover, ensure a zero-trust security model is in place which will only allow trusted users and devices to access your services.

5. Compliance Issue During Container Adoption

Compliance issues during implementation and managing containerized applications also known as container adoption is one of the most concerning security challenges. 

Compliance issues often arise during the container adoption process because teams rush to deploy containers without integrating necessary security measures. 

Failing to implement security standards, regulatory requirements, or internal policies arises security concerns like: 

• Unauthorized access: Without proper access controls, sensitive data or services are exposed to attackers.
• Data breaches: Neglecting encryption and secure data handling results in leaks of confidential information.
• Unpatched vulnerabilities: Skipping security updates in the container life cycle leaves the system open to known exploits.

Always incorporate security from the start of the container adoption process. Automate compliance checks to ensure your Kubernetes environment remains secure and aligned with regulatory standards.

Why Is Kubernetes Vulnerability Scanning Important?

Undetected Kubernetes vulnerabilities can lead to severe business and application impacts, including:

• Service Downtime: Vulnerabilities can disrupt services, leading to operational delays and lost revenue.
• Reputation Damage: Security incidents can erode customer trust, damaging the brand’s reputation.
• Customer Churn: Security breaches may push customers to switch to competitors, reducing the customer base.
• Increased Operational Costs: Addressing post-incident recovery, legal fees, and implementing reactive security measures can strain resources and increase costs.

The list goes on. Hence, it is crucial to thoroughly scan and detect vulnerabilities proactively at the earliest stages of Kubernetes deployments.

NIST defines vulnerability scanning as:
“A technique to identify hosts/host attributes and associated vulnerabilities.”

In the case of Kubernetes, vulnerability scanning is a preventative measure that ensures security gaps are identified and addressed before they can be exploited by malicious actors. 

Kubernetes scanning involves three major components:

• Container Image Scanning: This scans container images for vulnerabilities in the software packages, libraries, and dependencies that are bundled with the application. Identifying these issues early helps prevent running insecure images in production environments.
• Container File Scanning: This process inspects file systems within the container to detect malware, misconfigurations, and insecure files or permissions that could be exploited by attackers.
• Kubernetes Manifest Scanning: This scans Kubernetes manifests (YAML files) for misconfigurations in resource definitions, such as improper role-based access controls (RBAC), insecure networking policies, or overly permissive settings that could expose the cluster to attacks.

Regular container scans enhance security, ensure compliance, and optimize resources, enabling teams to focus on innovation instead of crisis management.

Stages Of Kubernetes Vulnerability Scanning

Instead of pushing the entire vulnerability scanning to the end of the application development cycle, experts advice to scan during each stage of application development. 

Before development

Before you deploy code, it’s better to run the source code through static scanning tools. Detecting misconfigurations and vulnerabilities early helps the development team to resolve them easily compared to embedded vulnerabilities after deployment. 

During deployment

Vulnerability scanning through the CI/CD pipeline ensures every build is secure. Each build is scanned automatically. The scanning process fits perfectly with the DevSecOps approach. This way, your team receives quick feedback and fixes issues faster. 

Do note that, as the project progresses, automatic scanning alone won’t suffice. You have to implement Kubernetes admission controllers to enforce security rules rigorously. 

For example, create a policy that automatically blocks any container images that are vulnerable. 

Post-deployment:

After the application is deployed, continue scanning through a runtime monitoring tool. This scans running containers and the Kubernetes environment identifies new vulnerabilities and evaluates security posture in real time.

Kubernetes Vulnerability Scanning: Are Free Tools Enough?

I have seen thousands of businesses relying only on free tools. While free tools like Trivy and Clair, offer basic scanning capabilities, using them alone is not a holistic approach to Kubernetes security. 

Free tools lack features like real-time monitoring, advanced threat detection, and integration with CI/CD pipelines. In fact, they do not provide detailed guidance to resolve the issue or support for custom policies. 

For organizations managing sensitive workloads or requiring compliance with strict regulations, free tools won’t be enough. 

I am not saying don’t use free tools; they can be a good starting point for basic security checks. However, relying solely on them can leave significant gaps in your security posture. 

For example, while Trivy might help you identify known vulnerabilities in your container images, it won’t alert you to new threats that emerge after deployment. Without real-time monitoring, you could be unaware of a security breach until it’s too late.

Hence, you can have a more robust security framework by complementing free tools with paid solutions that offer comprehensive features. By integrating tools that provide real-time alerts, advanced threat detection, and seamless CI/CD integration, you can ensure continuous security throughout the development lifecycle.

Kubernetes Vulnerability: Best Practices

Kubernetes vulnerabilities can harm a software project’s stability. This lead to several consequences for a software project including: 

• Less reliability
• Skyrocketing cloud cost
• Several security issues

As per a CNCF report, more than 96% of respondents found it difficult to align their strategy with best practices. 

The major reason for non-alignment often stems from a limited understanding of Kubernetes security best practices. Which is why it is important to understand the best practices in 2024 instead of following any outdated strategy. 

7 best practices you must include in your Kubernetes security strategy:

1. Enable RBAC to manage who can perform actions on the Kubernetes API. Define roles and bindings to restrict access based on user identities.
2. Secure ETCD with TLS encryption and firewall rules to protect sensitive data from unauthorized access.
3. Continuously scan container images and the Kubernetes codebase for vulnerabilities. Early detection allows for timely patches and mitigations.
4. Implement rules for inbound and outbound traffic to limit access to necessary services, helping to contain potential breaches.
5. Audit Logging: Enable audit logging to track all API requests. This provides insights into cluster activity and helps detect security issues.
6. Regularly update Kubernetes and its components to fix security vulnerabilities and stay protected.
7. Use process whitelisting to ensure only authorized processes can run in containers, preventing malicious activities.

Kubernetes Vulnerability Scanning: You Need More Than Just A Tool

While vulnerability scanning tools are a must-have for identifying risks in Kubernetes environments they alone do not make a comprehensive security. 

A comprehensive strategy involves continuous monitoring, proper configuration management, and implementing best practices for securing both containers and data. This approach ensures that vulnerabilities are not only detected but also effectively mitigated to protect the entire Kubernetes environment.

Furthermore, collaboration between development and security teams (DevSecOps) is important for integrating security into the entire lifecycle of applications. 

AccuKnox offers advanced runtime protection and machine learning-based threat detection, ensuring that vulnerabilities are not only identified but mitigated in real-time. Its seamless integration with Kubernetes environments enables teams to prevent risks proactively and respond quickly to security incidents.

By leveraging AccuKnox’s Zero Trust architecture and automated incident response, organizations can achieve a more resilient security posture, secure sensitive data, and maintain compliance with industry standards. 

Hence, instead of overinvesting in tools, create a comprehensive plan that helps your team proactively identify, address, and prevent risks throughout the process.