The Container Security Best Practices You Need To Be Using in 2025

Container security best practices are essential for protecting modern, cloud native applications from evolving threats. As organizations increasingly rely on containers for their speed, scalability and efficiency, securing them becomes more complex — and more critical. 

Unlike traditional workloads, containers are highly dynamic, ephemeral and often deployed at massive scale, which means even small missteps can lead to major vulnerabilities. From image integrity to runtime behavior and network isolation, every stage of the container lifecycle presents opportunities for strengthening security, as well as potential risks. 

In this blog, we’ll break down the most important best practices you need to follow to keep your containerized environments secure and resilient.

What is container security?

Container security refers to the tools, practices and policies used to protect containerized applications throughout their lifecycle, from development and deployment to runtime. Containers offer flexibility and scalability by packaging applications and their dependencies into lightweight, portable units. But with that speed and portability come unique security challenges. Containers are often short-lived, deployed at high volume and operate in dynamic environments — all of which can create more opportunities for misconfigurations, vulnerabilities or unauthorized access.

That’s why container security is critical. Without proper protections in place, a single compromised container could expose sensitive data, disrupt workloads or create an entry point for attackers. Securing containers helps ensure that images are free of known vulnerabilities, runtime behavior is monitored, access is tightly controlled, and network traffic is properly segmented. In modern cloud-native environments, where applications are built from many loosely coupled components, container security isn’t optional — it’s essential for maintaining trust, availability and control.

SUSE provides enterprise-grade container security across the entire lifecycle with an integrated, open platform. SUSE Security delivers real-time runtime protection, Kubewarden enforces flexible policies with WebAssembly, and SUSE Observability offers deep visibility into workloads and cost. These capabilities help organizations deploy containers securely — at scale and across clouds, data centers and edge environments.

What are containers?

Containers are a lightweight form of virtualization that package an application’s code together with its dependencies, libraries and configuration files into a single, portable unit. Unlike traditional virtual machines, containers don’t require their own operating system. Instead, they share the host OS kernel while running in isolated user spaces. This makes them fast to spin up, efficient in resource usage and easy to deploy consistently across different environments.

Containers play a critical role in modern application development and deployment. They allow developers to build applications that can run reliably anywhere, like on a developer’s laptop, in a test environment or in production on a cloud platform. This consistency helps eliminate the “it works on my machine” problem and enables DevOps practices like continuous integration and continuous delivery (CI/CD). Containers are also essential to microservices architectures, where applications are broken into smaller, independently deployable services that can be scaled and updated individually.

Companies often use containers because of the many advantages containers offer, such as:

• Faster application development and deployment – Containers streamline the build-test-deploy cycle, enabling quicker releases and updates.
• Consistency across environments – Applications run the same in development, testing and production, reducing bugs caused by environment differences.
• Improved scalability – Containers can be easily scaled up or down to meet demand without affecting the rest of the application.
• Efficient resource utilization – Containers use fewer system resources than traditional virtual machines, allowing higher density on the same hardware.
  Support for microservices architectures – Containers make it easier to develop, deploy and manage individual services independently.
  Simplified maintenance and troubleshooting – Isolated workloads help teams quickly identify and resolve issues without impacting other services.
• Portability across platforms – Containers can run on any infrastructure that supports the container runtime, from laptops to public cloud environments.
• Better DevOps integration – Containers work well with CI/CD pipelines, infrastructure as code and automation tools, enabling smoother workflows.

What are the risks of using containers?

While containers offer many business advantages, they also have some security risks that are essential to manage. While containers offer speed, scalability and portability, they also introduce unique vulnerabilities that don’t always exist in traditional environments. From misconfigurations to advanced supply chain threats, understanding where containers are exposed is the first step in building a strong security posture.

Untrusted or vulnerable images

One of the most common risks in container environments is the use of base images that contain known vulnerabilities or outdated dependencies. Developers often pull images from public registries without verifying their source or scanning them for issues. If a compromised image is used to build multiple services, it can spread risk across the entire environment. Regular image scanning and tight control over what enters your container ecosystem are essential to reduce exposure.

Excessive privileges and insecure execution

Running containers with unnecessary privileges or root access can create major security gaps. Containers should operate with the least amount of access required to do their job, but too often, they are launched with elevated permissions or broad host-level access. This increases the risk that an attacker could gain control of the host system or escalate access beyond the container itself.

Weak or inconsistent configuration

Containers can be deployed quickly, which makes them easy to misconfigure. Insecure defaults, exposed ports or open network policies are all examples of configuration errors that can expose services to the public or allow unwanted internal communication. Without standardized configuration practices and automated checks, security gaps can go unnoticed until they’re exploited.

Lack of visibility and audit trails

Many teams struggle with limited visibility into what’s happening inside containers, especially once they’re deployed and running at scale. If logs are incomplete or not collected centrally, it becomes difficult to trace actions, detect anomalies or respond to incidents. This lack of observability can lead to longer response times and makes compliance reporting more difficult.

Compromised supply chain components

Containers rely on layers of software from various sources — base images, packages and third-party tools. If any link in that supply chain is compromised, it can introduce malicious code into the container without detection. Supply chain attacks are growing in sophistication and are particularly dangerous because they exploit trust in widely used components or automated CI/CD pipelines.

Noncompliance with security and data standards

Containers can make it harder to maintain consistent governance, especially in highly regulated industries. Without proper controls, teams may deploy containers that store sensitive data insecurely or fail to meet requirements for auditability and data protection. Compliance risks include violations of frameworks like HIPAA, PCI DSS or GDPR, all of which can result in fines or reputational damage.

Lateral movement and container breakout

In poorly isolated environments, attackers can break out of a compromised container and move laterally across the infrastructure. This kind of container escape can lead to access of other containers, hosts or internal services. Without strict network segmentation and runtime protections in place, one weak container can become a stepping stone to much broader compromise.

Unrestricted network exposure

Containers often communicate with each other across internal networks, but without proper controls, this traffic can become a serious liability. Open ports, weak firewall rules or lack of network segmentation can allow attackers to scan for exposed services or move between containers undetected. If containers are unintentionally exposed to the public internet, they can become easy targets for brute-force attacks or unauthorized access. Implementing strict network policies and isolating workloads based on function or sensitivity is essential to reduce the attack surface.

Poor secrets management

Containers frequently need access to credentials, API keys or tokens to perform tasks — but if those secrets are hardcoded into images or stored in environment variables, they become easy to extract. Mismanaged secrets can lead to unauthorized access to databases, internal APIs or cloud infrastructure. Without a centralized secrets management solution and strict access controls, it’s difficult to protect sensitive information and rotate credentials securely across deployments.

The ephemeral nature of containers

Containers are designed to be short-lived and highly dynamic, which makes them ideal for scaling applications quickly, but also difficult to monitor and secure. Containers can spin up and disappear in seconds, making it easy for malicious activity to go undetected if logging and alerting aren’t properly configured. This ephemerality also complicates forensics and incident response, as evidence may be lost once a container is terminated. Without persistent monitoring and container observability, it’s hard to ensure consistent enforcement of security policies across rapidly changing environments.

Where do containers need to be secured?

Securing containers isn’t just about locking them down at runtime; it requires protection across the entire lifecycle. From the moment a container image is built to how it’s stored, deployed and run in production, each stage introduces unique risks that need to be addressed. Understanding where containers need to be secured helps ensure no weak link is left exposed. Here are some critical areas where containers need to be secured, and what can happen if it’s not done correctly. 

Container security best practices

Securing containers requires a comprehensive approach that covers every stage of the container lifecycle, from building and storing images to running them in production. Because containers are often deployed at high speed and scale, security needs to be automated, consistent and integrated into your workflows. Below are best practices for some of the most critical areas of container security that correspond with the security needs in the previous section of this article. 

Images

Start with clean, trusted base images. Avoid pulling random images from public sources without verification, and instead use images from official repositories or internally vetted sources. Regularly scan images for known vulnerabilities before and after deployment, and minimize the number of layers and packages to reduce the attack surface. Use tools that support image signing to validate image integrity and ensure you’re not deploying something tampered with or outdated.

Registries

Secure your container registries just like any other sensitive infrastructure. Use private registries for internal images and enforce access controls to limit who can push, pull or modify image content. Enable vulnerability scanning and logging within the registry itself, and integrate it with CI/CD pipelines to automatically block risky images from moving downstream. Encrypt images in transit and at rest to prevent unauthorized access or tampering.

Runtime

Once containers are running, continuous visibility and control are key. Use tools that monitor container behavior to detect anomalies, such as unusual network connections or system calls. Run containers with the least privileges necessary and avoid using the root user unless absolutely required. Enable read-only file systems where possible, and make sure container runtime security policies are in place to limit access to sensitive resources or kernel-level functions. SUSE is the only major container platform offering runtime behavioral security, WebAssembly policy-as-code, and integrated observability in a single open platform.

Network

Container networking is flexible but can also introduce risk if not properly configured. Isolate workloads using namespaces, service meshes or Kubernetes network policies to limit communication between containers. Only expose necessary ports and restrict ingress and egress traffic based on function. Use TLS encryption for all data in transit and monitor traffic patterns for signs of lateral movement or external scanning attempts.

Container execution

Containers should be executed with the principle of least privilege in mind. Avoid running containers as root or with unnecessary elevated privileges, as this increases the risk of host compromise. Capabilities should be dropped by default, and access to sensitive host resources (such as the file system, Docker socket or kernel modules) should be restricted unless explicitly required. Runtime security tools can help enforce these controls and monitor for abnormal execution behavior that might indicate a breach.

Configuration

Misconfigurations are one of the most common sources of container vulnerabilities. Using secure defaults, applying configuration-as-code practices and performing automated configuration audits help ensure that containers are deployed consistently and securely. Limit open ports, enforce read-only file systems when possible, and define environment variables carefully to avoid exposing secrets or sensitive data. Configuration validation should be baked into the deployment process to catch risks before containers are launched.

Monitoring and logging

Robust monitoring and logging are critical for detecting threats and responding to incidents in container environments. Implement centralized logging to collect data from across your containers, hosts and container orchestration platforms. Track metrics like container uptime, network activity and unexpected restarts, and set up real-time alerts for suspicious behavior. Audit logs should be retained securely and reviewed regularly to ensure accountability and support forensic analysis in the event of a breach.

Supply chain

The container supply chain includes everything from code dependencies to CI/CD tools and third-party integrations. To reduce risk, validate and sign all software artifacts, including container images, before they reach production. Scan dependencies for vulnerabilities and use software bill of materials (SBOM) tracking to understand what’s in every build. Secure your CI/CD pipelines with strong authentication, minimal access permissions and audit logs to prevent unauthorized code changes or image tampering.

Governance and compliance

To meet regulatory standards and internal policies, containers must be deployed and managed with clear governance controls. Implement role-based access control (RBAC) to manage who can deploy, modify or access container workloads. Maintain an audit trail of changes and access, and automate policy enforcement using tools that support compliance frameworks like HIPAA, PCI DSS or GDPR. Consistent documentation and standardized deployment practices are also essential for maintaining compliance across environments.

Container isolation

Strong isolation between containers is key to preventing lateral movement if one container is compromised. Use namespaces, cgroups and kernel security features to isolate containers from each other and from the host system. Apply network segmentation to limit which containers can communicate with one another, and consider using service meshes or network policies for fine-grained traffic control. Avoid sharing host resources unnecessarily, and regularly test for escape vulnerabilities to ensure that each container remains properly contained.

Best practices for container security are proactive, practical steps that help protect your applications and data from a wide range of threats. While no security strategy can guarantee complete protection, following these best practices significantly reduces risk and strengthens your overall defense. They help catch issues early, minimize vulnerabilities and ensure your containers are deployed with security in mind, not as an afterthought. The effort you put into securing your containers is well worth it when it means fewer incidents, faster response and greater confidence in your infrastructure.

How SUSE provides container security

SUSE supports container security by providing a comprehensive, enterprise-grade platform that integrates security across the entire container lifecycle. With solutions like SUSE Rancher Prime, organizations can manage Kubernetes clusters at scale while enforcing consistent security policies across environments. When combined with container security best practices, SUSE can proactively protect your containers and skyrocket your application efficiency and performance. 

Security is needed at every stage of the container lifecycle. SUSE’s approach ensures coverage across build, deploy, and runtime phases, using open, integrated tooling.

SUSE also enables secure image management, centralized access control and automated deployment pipelines, all backed by role-based access and governance tools. It also supports integration with popular security tools for image scanning, runtime protection and compliance monitoring, helping teams detect and respond to threats faster. Whether you’re running containers on-prem, in the cloud, or at the edge, SUSE gives you the visibility, control and flexibility to secure your containerized workloads with confidence.

With SUSE, you can implement these best practices using an integrated, enterprise-grade platform. SUSE Security, Kubewarden, and SUSE Observability deliver runtime protection, flexible policy and platform insights — all backed by open source and long-term support. Learn more about SUSE Security.

Container security best practices: Final thoughts

Securing containers is no longer optional — it’s a critical part of protecting modern applications and infrastructure. By following container security best practices across images, configuration, runtime and networking, organizations can reduce risk and build a stronger, more resilient environment. As containers continue to power everything from development to production, taking a proactive approach to security ensures your workloads stay protected, your teams stay efficient and your business stays ahead of evolving threats.

To protect your containers, learn more about the only fully open source, zero trust container security platform: SUSE Security. 

Container security best practices FAQs

Have questions? We have answers. Container security is vital for making sure your organization runs smoothly and safely, so we’re here to make sure you have all the info you need to make smart decisions about your containers. 

Are containers a security risk?

Containers themselves aren’t inherently insecure, but they do introduce new security challenges that organizations need to manage carefully. Because containers are lightweight, portable and often short-lived, they can be deployed and scaled rapidly — which means misconfigurations, unpatched vulnerabilities or weak access controls can quickly propagate across environments. Additionally, containers typically share the host OS kernel, so if one container is compromised and not properly isolated, it may lead to broader system access. Risks also arise from poorly secured container images, inadequate monitoring, and overly permissive runtime privileges. That said, containers can be highly secure when best practices are followed, such as using trusted images, enforcing least privilege, securing network traffic and applying runtime protection. The real risk comes not from containers themselves, but from overlooking the unique security needs they require in fast-moving, cloud-native environments.

What are the benefits of using containers?

Containers have become a cornerstone of modern application development because they offer a powerful combination of consistency, speed and scalability. By packaging an application with all of its dependencies, containers ensure that it runs reliably across different environments — from a developer’s laptop to a production cluster in the cloud. This consistency reduces environment-related bugs and simplifies testing and deployment processes. Containers are also lightweight, allowing for faster startup times and more efficient use of resources compared to traditional virtual machines. They’re particularly well-suited for microservices architectures, where applications are broken into smaller, independently deployable services that can be updated or scaled on demand. Ultimately, containers help teams move faster, innovate more freely and maintain greater flexibility in how they build, ship and run software.

Which is the best container security tool?

The best container security tool is one that aligns with your organization’s infrastructure, scale and security goals — and effectively covers the entire container lifecycle. A strong tool should provide comprehensive image scanning to detect vulnerabilities before containers are deployed, as well as runtime protection to monitor container behavior and detect anomalies in real time. Integration with CI/CD pipelines is critical for catching issues early and enforcing policies automatically during development. Look for tools that offer role-based access controls, secrets management, and network visibility, allowing you to manage who has access to what and monitor how containers communicate internally and externally. Scalability, ease of use and support for your orchestration platform (like Kubernetes or ECS) are also key. Ultimately, the best tool is one that fits into your existing workflows, minimizes friction for developers and provides the security team with clear visibility and control.