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What is container security?

Learn about the key components of container security and best practices, strategies, and tools that will help you improve container security at your organization.

Container security defined

Container security refers to the processes, policies, and tools used to protect containerized applications from threats. 
As the popularity of containers continues to grow, the importance of container security has increased exponentially. For many organizations, container security has become an essential part of cloud security.

What are containers?

Before we get into container security, let’s go over what a container is and some of the advantages to using them. Containers are units of software that package application code with its libraries and dependencies. This allows containers to be deployed seamlessly across on-premises, hybrid, cloud, and multicloud environments. There are numerous benefits of using containers, such as:

  • Scalability

    Containers are highly scalable because of their lightweight builds and small file sizes. Since containers do not have the overhead typical of VMs, many more containers can be supported on the same infrastructure. The lightweight nature of containers means they can be started and stopped quickly, unlocking rapid scale-up and scale-down scenarios.

  • Portability

    Containers carry all of their dependencies with them, which means they can be written once and run on any environment. Any time a container is deployed, it executes in a consistent environment that remains unchanged from one deployment to another.

  • Efficiency

    Because apps written in containers don’t have to be reconfigured to run on new environments, they can be deployed relatively quickly and efficiently.

  • Isolation

    Containerized applications run in their own isolated environments, which prevents conflicts with other applications. Isolation also helps limit the impact of security breaches.

Why is container security important?

Protecting containers from security threats ensures that the applications and data they contain are safe. For organizations reliant on containers, container security can be essential to maintaining business continuity. 

There are numerous benefits to securing containers at your organization, including:

  • Risk mitigation. The likelihood of security breaches, unauthorized access, data leaks, and other security incidents decrease when your containers are secure.
  • Accelerated development. Mitigating the security risks associated with containers empowers your developers to create and deploy containerized applications with confidence. 
  • Decreased costs. Safely developing and deploying applications through containers requires fewer resources than traditional deployment methods. 

How does container security work?

Strong container security is achieved through practices, tools, and technologies that are used in tandem to protect container environments and mitigate security risks. It requires a multilayered approach that will vary depending on the needs of your organization. That said, the primary components of container security include isolation, container image security, runtime security, network security, logging and monitoring, and vulnerability management. Here’s more info about each component:

  • Isolation

    Isolation ensures each container has its own isolated file system and process space to prevent containers from interfering with each other. Enforcing isolation also limits the impact of security breaches if they do occur.

  • Runtime security

    A container runtime is the software component that containers run on and are managed from. Runtime security protects your containers while they’re running. Container runtime environments should only come from trusted sources, like Dockers or Kubernetes, and should be regularly updated.

  • Container image security

    Like runtime environments, container images should only be sourced from trusted providers. It’s important to keep your container images up to date with security patches and updates. Regularly updating and patching container images ensures that their attack surface is minimized by removing any unnecessary packages and dependencies.

  • Network security

    Container networks allow containers to communicate with other containers and with external systems. Networks should be configured to tightly control this communication to limit the possibility of network security breaches.

  • Logging and monitoring

    Logging and monitoring container data helps you detect threats before they occur by providing notifications about any potential or active security breaches. To effectively log and monitor container data, you should track key metrics like network traffic, resource usage, security incidents, and performance. Agentless scanning technology is often used to monitor containers.

  • Orchestration security

    A container orchestration platform is a software framework that helps you manage, deploy, scale, and monitor containers. It performs the automated elements of deploying and managing containerized applications. Orchestration security helps protect the containerized environment and the orchestration platform itself. The key elements of orchestration security are secure cluster configurations, access control, and strictly enforced security policies around orchestration.

Key challenges in container security

The popularity of containers makes them an appealing target for attackers. While there are security advantages to using containers, such as isolation, they also present new vulnerabilities. Some of the primary security risks associated with using containers include:

  • Container images built from pre-existing images may have insecure configurations that are vulnerable to attack.
  • Actively monitoring containers is sometimes difficult due to their dynamic nature. This can make it harder to detect threats.
  • Compromised untrusted containers uploaded to public repositories may have malware coded into them by attackers or insecure configurations.
  • The container-to-container and container-to-host networks that containers rely on to communicate are vulnerable to breaches and unauthorized access if they’re not properly configured and monitored.
  • Some organizations struggle with a lack of security expertise around containers.

Fortunately, implementing container security best practices can help you ensure that your containers are protected from these and other security challenges. 

Container security best practices

Container security best practices are designed to help you mitigate vulnerabilities, reduce the attack surface of your containers, quickly detect breaches, and stay ahead of emerging threats.

Here are some container security best practices to consider implementing at your organization:

  • When sourcing container images, only use trusted sources. These include official repositories and reputable vendors. Container images from untrusted sources are more likely to contain malware or be built from insecure configurations. Scan all of your container images should be before you use them, regardless of their source.
  • Enforce strong authentication and access controls on your containers and their orchestration platform.
  • Run containers with least privileges granted to the least amount of employees necessary to perform the container’s intended function.
  • Continuously scan container images during the development progress. Scanning containers at every stage of development helps identify vulnerabilities before containers are deployed.
  • Use automated scanning tools to identify threats. Automated scanning tools take some of the guesswork and potential for human error out of the scanning process.
  • Keep everything updated. Your containers, security tools, container images, and runtimes must be regularly updated and patched to stay secure. 

These best practices are a great starting place for any organization looking to improve its container security. That said, tailor your container security practices to the needs of your organization. When drafting container security best practices, consider your organization’s risk tolerance levels, compliance requirements, and operational environments. 
Once your container security best practices have been implemented, continuously review and adjust them as the needs of your organization and the container security landscape change.

Types of container security tools

In addition to best practices, there are a few different types of tools that can help you strengthen container security at your organization.

Container vulnerability scanners
Container vulnerability scanners analyze container images for security flaws like insecure configurations and malware. After scanning is complete, container scanners typically produce a report that includes recommendations for fixing security vulnerabilities. Containers have many components, and scanners help you more efficiently assess them all for threats.

Container runtime security tools
Runtime security tools are used to protect containers from threats and vulnerabilities once they’ve been launched in the runtime environment. They monitor the runtime environment for suspicious activities, unauthorized access, and other security threats.

Container network security solutions
Container network security solutions are designed to protect the networks that allow for container-to-container and container-to-host communication. Using firewalls, network segmentation, and encryption, these tools help decrease the risk of network-based container attacks.

Container monitoring solutions
Container monitoring solutions track and log event data and container performance. Continuous monitoring helps you determine the cause of events like failures and prevent them from occurring. It also provides a window into how resources are being used so that you can optimize their allocation. Comprehensive cloud security posture management (CPSM) systems are effective for monitoring container environments.

As you might have gathered, there are tools available that address almost every facet of container security. Researching, identifying, and employing the right tools is a great way to improve container security at your organization.

Secure your containerized environments

Containers offer numerous benefits, such as scalability, portability, and efficiency. For the organizations who use them, securing containers not only protects valuable assets and data—it empowers continued growth and innovation. If your organization is looking to fortify its container security while improving your overall cloud data security, consider using a cloud workload protection platform (CWPP) and cloud access security broker (CASB).

Learn more about Microsoft Security

Cloud workload protection solutions

Detect and respond to attacks in real time to protect multicloud, hybrid, and on-premises workloads.

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Microsoft Defender for Cloud

Protect your multicloud and hybrid cloud workloads with built-in XDR capabilities.

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Microsoft Defender for Cloud Apps

Modernize how you secure your apps and protect your data.

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Microsoft Cloud Security Posture Management

Strengthen posture across multicloud and hybrid environments with contextual security.

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Frequently asked questions

  • One example of container security is the use of vulnerability scanners to analyze container images for security flaws like malware or insecure configurations.

  • There are a few steps to securing a container:

    1. Only use container images from trusted sources.
    2. Enforce strong authentication and access controls.
    3. Continuously scan containers and runtime environments for security vulnerabilities.
    4. Regularly update and patch all containers, security tools, container images, and runtime environments.

  • The key components of container security are isolation and resource control, container image security, runtime security, network security, orchestration security, logging and monitoring, and vulnerability management.

  • Container security scanning is the process of analyzing container images for security vulnerabilities.

  • Container image security refers to measures taken to ensure container images are safe to use.

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