Container Security for Beginners: Basics and Best Practices

In this beginners guide, we'll explore all the basics, strategies and best practices for container security in software development

Updated on November 29, 2023
Container Security for Beginners: Basics and Best Practices

What Is Container Security?

The world of software development has significantly evolved over the years, with containerization being one of the most crucial advancements. Containers have made it possible to package and run applications in any environment smoothly, reducing the challenges of software compatibility.  In this beginners guide, we’ll explore all the basics, strategies and best practices for container security in software development.

Container security refers to the processes, policies, and technologies that protect containerized applications from threats and exploits. It encompasses the security measures implemented throughout the container lifecycle, from creation to operation and even post-deletion. Container security is critical because it safeguards the applications running within the containers, the underlying infrastructure, and the larger network in which they exist.

Just like traditional application security, container security also deals with protecting against malicious attacks, data breaches, and vulnerabilities. However, it has unique aspects due to the architectural differences between traditional virtualization and containerization. As a result, container security requires unique strategies, tools, and best practices.

Core Components of Container Security

Container Security for Beginners: Image Security

Image security is the first line of defense in securing your containerized applications. Container images are the basis upon which containers run, and if the image is compromised, the container running it is also at risk.

Image security involves ensuring that the container images used to run your containers are secure and free from vulnerabilities. It includes validating the source of the images, scanning for vulnerabilities, and managing image versions. Image security is not a one-time task but an ongoing process, as new vulnerabilities can be discovered at any time.

Furthermore, image security also requires managing who can access and modify your container images. This includes implementing role-based access control, auditing image changes, and tracking image use across your environment.

Container Runtime Security

Runtime security pertains to the safety measures in place while the container is active or ‘running.’ Runtime security involves monitoring the container’s behavior to detect and prevent malicious or anomalous activity.

As part of runtime security, you should implement controls to restrict container access to resources, isolate containers from each other and the host system, and monitor container processes. Additionally, runtime security involves analyzing logs and other data to identify potential security incidents.

You should also have procedures in place to respond to security incidents detected during runtime. This includes isolating compromised containers, mitigating the impact, and identifying and addressing the root cause of the incident.

Container Security for Beginners: Network Security

In a containerized environment, containers often communicate with each other and external systems over the network. Therefore, securing this network communication is critical.

Network security in a container context involves implementing network policies to control the traffic between containers and between containers and external systems. It also includes monitoring network traffic to detect anomalies and potential security threats.

Additionally, network security involves securing the container orchestration platform’s control plane, which manages the container network. This includes securing communication between the control plane components, restricting who can access the control plane, and auditing control plane activity.

Best Practices for Securing Container Images

Having understood the core components of container security, let’s now explore some of the best practices for securing container images.

Container Security for Beginners: Using Trusted Base Images

When creating container images, it’s crucial to start with trusted base images. Not all images available on public repositories are safe to use. Unverified or untrusted images can contain hidden malware or vulnerabilities that can compromise your containers.

Therefore, it’s advisable to use base images from trusted sources, such as official images from software vendors or images from verified public repositories. Additionally, you should regularly update your base images to incorporate the latest security patches and updates.

Regularly Scanning for Vulnerabilities and Dependencies

Another best practice for securing container images is regular vulnerability and dependency scanning. As mentioned earlier, new vulnerabilities can be discovered at any time. Therefore, it’s essential to regularly scan your images for known vulnerabilities and outdated or insecure dependencies.

There are several tools available that can automate this process, alerting you when a vulnerability is found and often suggesting remediation steps. Regular scanning not only helps you catch vulnerabilities early but also fulfills compliance requirements in many cases. In this beginners guide, we’ll explore all the basics, strategies and best practices for container security in software development.

Minimizing the Footprint of Images

The last best practice we’ll discuss is minimizing the footprint of your container images. The larger the image, the more potential it has for vulnerabilities and attacks. Therefore, it’s advisable to keep your images as small and simple as possible.

This involves using minimal base images, removing unnecessary files and packages, and following the principle of least privilege, i.e., only including the permissions and capabilities necessary for the application to function. Minimizing the image footprint not only enhances security but also improves container performance and startup times.

Best Practices for Container Network Security

Here are some additional best practices that can help you ensure container network communications are secure.

Network Segmentation and Microsegmentation

In container network security, network segmentation and microsegmentation are vital practices. Network segmentation involves dividing the network into smaller parts or segments, each with its security controls. This way, if one segment is compromised, the impact on the rest of the network is limited.

Microsegmentation takes this concept a step further by implementing security controls at a granular level. It allows you to define security policies for individual workloads or even single processes within a container. By applying microsegmentation, you can provide a higher level of protection and control over your containerized applications. In this beginners guide, we’ll explore all the basics, strategies and best practices for container security in software development.

Firewalling and Filtering

Firewalling and filtering are significant components of container network security. These practices involve the use of firewalls to control the traffic entering and leaving your containers and filtering to block or allow specific types of traffic based on predefined rules of basics in container security.

Firewalls are an essential tool for protecting your containers from unauthorized access. They can help you prevent unwanted traffic from reaching your containers and block outgoing traffic that could indicate a security breach. Meanwhile, filtering can help you control the data that’s allowed to pass into and out of your containers, providing an additional layer of security.

Encrypting Data in Transit

Encrypting data in transit is another essential best practice for container network security. It involves encoding your data to prevent unauthorized access while it’s being transferred from one place to another.

When data is encrypted, it’s transformed into a format that can only be read by authorized parties who have the decryption key. This ensures that even if the data is intercepted during transit, it remains secure and inaccessible to unauthorized users. Encrypting data in transit is particularly crucial when transmitting sensitive information, such as user credentials or confidential business data.


In conclusion, container security is an essential aspect of modern software development practices. As containers continue to play a critical role in the deployment and distribution of applications, understanding and implementing the best practices for container security is of paramount importance. By adopting these practices, you can ensure the security of your containerized applications and protect your systems from potential threats.

Author Bio: Gilad David Maayan

Gilad David blog author David Maayan

Gilad David Maayan is a technology writer who has worked with over 150 technology companies including SAP, Imperva, Samsung NEXT, NetApp and Check Point, producing technical and thought leadership content that elucidates technical solutions for developers and IT leadership. Today he heads Agile SEO, the leading marketing agency in the technology industry.