What Is Container Security?

Container Security Definition

“Container security is the practice of managing security risks that could affect containers across all stages of the software development lifecycle (SDLC). It includes processes such as scanning of securing the code inside containers, scanning container images prior to deployment and monitoring container-based runtime environments”

If you had to pick a single technology that has had the greatest impact in changing software development practices over the past decades, containers would be a good choice. Although container technology isn’t new – it traces its roots to the 1970s – the widespread adoption of containers since the launch of Docker in 2013 has dramatically altered software development by making containers the go-to approach to packaging and deploying applications across all stages of the software development lifecycle (SDLC).

However, the new development practices that containers have enabled also raise challenges due to container security risks. When containers are the heart of software delivery pipelines, container security becomes a paramount concern for organizations of all types.

With that reality in mind, keep reading for a look at what container security entails, why it’s important, and best practices for securing containers.

What are containers?

Containers are a lightweight virtualization technology that makes it possible to package an application’s entire runtime environment into one file. This approach provides a consistent runtime environment regardless of the underlying host operating system. It also offers some security benefits because applications are partly isolated from the host and each other.

What is container security? 

Although isolating applications inside lightweight virtual environments provides some security benefits, containers are also subject to special types of security challenges. Addressing those challenges is the purpose of container security.

Container security is the process of detecting and mitigating security risks for containerized applications at all stages of the SDLC – from initial application development, to packaging of apps inside containers, to deployment of containers in production.

Container security as part of the development lifecycle

To make container security as efficient and effective as possible, it’s a best practice to integrate container security processes directly into the software development lifecycle. Key processes in this regard include:

  • Scanning source code and binaries before they are packaged into container images. This reduces the risk of having to rebuild images because you discover a security problem later in the SDLC.
  • Scanning container images to identify issues inside the images (such as startup commands that install vulnerable dependencies) that may create security risks.
  • Ensuring that the registry that hosts container images has proper access controls in place to prevent unauthorized access to and modification of images.
  • Monitoring of containers after deployment to detect unusual behavior that could stem from attacks or breaches.

The importance of container security 

Container security is critical because using containers adds many layers to your software hosting stack that would not exist in a traditional application development strategy. Vulnerabilities in any part of the software stack that hosts containers – which include not just containers themselves, but also the runtime software that operates containers, as well as orchestration tools (like Kubernetes) that help manage containers – could result in a breach.

How does it work?

Container security works by combining standard software security tools and processes with ones tailored to the unique challenges of containers. For instance, Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST) can uncover risks in software before it is packaged into containers.

Then, container security scanning tools can validate that container images are secure prior to deployment. After deployment, container security monitoring software designed to interpret data from platforms like Kubernetes or Docker can alert teams to unusual or risky behavior (such as containers that are running as root) within production environments.

Benefits of container security

The main benefit of container security is that it allows organizations to take advantage of containers while keeping the associated security risks in check.

As we’ve explained, containers introduce additional risks that wouldn’t exist in a conventional, non-containerized software environment. However, they also offer a range of benefits, such as the ability to move applications more easily across different servers (because the underlying server environment has little impact on how containerized applications run) and the isolation of applications from each other.

These advantages mean that containers can streamline software development and deployment – so there is good reason to use containers. But it’s important to deploy container security tools and processes to ensure that the security risks of containers don’t outweigh their benefits.

Container security risks

The main types of container security risks include:

  • Vulnerable application code or malware inside container images.
  • Configuration oversights that expose containers to attacks.
  • Vulnerabilities or misconfigurations in container runtimes (the software that operates containers).
  • Tampering with container images by threat actors inside registries (which is where container images are typically hosted prior to being deployed).
  • The deployment of outdated containers that are subject to known risks. This can happen when engineers download (or “pull”) container images without specifying an image version, causing their tools to default to using a vulnerable image.

An effective container security strategy defends against all of these risks.

Best practices for container security

There are many practices that can help mitigate container security risks. Among the most important are:

  • Scan container application code and images at all relevant stages of the SDLC.
  • Never download container images from an untrusted registry.
  • Avoid running containers as root, since this makes it easier for attackers who breach one container to use it as a beachhead for breaching other containers or the host operating system.
  • Use a minimalist operating system to host containers. This reduces your attack surface, minimizing the risk that breaches against the operating system could escalate into attacks against containers.
  • Specify container image versions when downloading images so that you know exactly which version you are running.
  • Validate that registry paths and container names are accurate to prevent typosquatting attacks.

Securing containers with Checkmarx

As a comprehensive application security platform, Checkmarx has you covered when it comes to container security. Checkmarx scans for container security risks at all stages of the SDLC – from code to cloud – to maximize your ability to detect and fix issues before they lead to attacks. In addition, container security risk prioritization features make it easy for teams running large numbers of containers to determine which security issues pose the greatest threat, so they can respond efficiently.

Learn more about Checkmarx’s container security solution by requesting a demo.