There has been an immense increase in the adoption of container technology for software development and production. However, Docker containers are a lot more complex than virtual machines or the other forms of deployment technologies that were used before them.
Earlier technologies usually had only two layers to secure, which are the host environment and application. Organizations did not have to worry about APIs, network overlays, or storage configurations. However, modern Docker container environments have a lot of moving parts, such as:
That is why it is necessary for organizations using Docker containers to learn how to secure them. These are some of the best practices that can help optimize Docker container security systems at your organization.
Set up Resource Quotas
Docker systems allow you to configure the resource quota for individual containers. You can use the resource coders to limit the consumption of memory and CPU usage. The feature is quite useful due to several reasons.
You can prevent a single container or application from taking up too much memory or CPU usage. That way, if one of them gets compromised, the system will prevent it from using too many resources required to disrupt the services or execute malicious commands. You can use command-line flags to set up resource quotas with ease.
Do Not Run Applications as Root
Developers do not want to struggle with permission settings to run an application and thus, end up running it as root. It might be permissible in a Docker testing environment when a developer is trying to learn.
However, it should not be permitted in production to allow a Docker container application to run with root permissions. The default settings for Docker systems do not allow containers to run with root permissions, so developers should let the container application run as default.
Therefore, you must direct your developers to prioritize security over convenience. If you use Kubernetes for additional Docker security in container organization, you can modify the pod security policy using the MustRunAsNonRoot command.
Secure the Container Registries
Container registries make it very easy to set up central storages from which developers can download container images conveniently. However, the same convenience can become a security risk if the developers do not evaluate the necessary security context of the container registries they are using.
Ideally, they should use a Docker Trusted Registry (DTR) installed behind the firewall. It will reduce the risk of Internet breaches. Additionally, you should limit the authorizations to upload or download images from a registry. You can create access controls depending on a person’s role in your organization.
Use Secure Images From Trusted Sources
This point may seem obvious. However, developers are often tempted by the availability of public container images. Sometimes, they might download one from an unverified source.
Therefore, it is best to blacklist public container registries and direct your developers to use images from trusted sources like those on Docker Hub. You can also implement image scanning tools that scan registries to identify any known vulnerabilities present in Docker images. Some enterprise-level registries also have the option to scan individual images for vulnerabilities.
Identify the Source of Codes
Since we are discussing the source of images, you should also remember that Docker images have a mix of original codes and containers from other sources. Therefore, even if the container is from a trusted registry, it may have supporting images from unverified sources.
Furthermore, they might have been written with codes assimilated from multiple sources, including third-party or open sources. In such cases, source code analysis tools can come in handy. Developers can use it to scan all the downloaded Docker images and identify their sources.
That way, they will know whether the images might contain any security vulnerabilities. Using a source code analysis tool will also help you with legal compliance for the license to use third-party codes.
Ensure API and Network Security
As mentioned above, Docker containers have to rely extensively on APIs and network to interact. You must ensure that the API and network structures used at your organization have secure designs.
Also, they should get monitored regularly for irregularities and breaches. APIs and networks are usually not a part of Docker configuration but external resources. Therefore, you have to take additional steps to secure them when you use them for Docker containers.
Docker environments are extremely useful for software development. But you may find it complicated to maintain container security. While we may not have included the technical knowledge for Docker security, we hope you find these practices useful for your organization.