Container Risks and Best Practices

Over the past years, containerization has increased demand as a powerful solution to application deployment and migration; however, this has not fallen short of challenges; among them security risks.

Whether you are developing your application from scratch or migrating your monolithic application to a containerized environment, here are some most common container security risks you should be aware of;

  • Containers running with the privileged flag.

A container running on the privileged flag means; that it has rights similar to its host. A breach of container security can easily enable the attacker to escalate.

  • Using images that are not secure

Some of the images used as base images could contain vulnerabilities such as embedded malware, untrusted images, e.t.c.

  • Malicious/rogue process running on containers.

In environments where containers have a short lifespan, monitoring the processes running in the containers may be challenging. These malicious processes may sometimes be unrelated to the container requirements. Some of these malicious processes may include; reverse shells and remote code injections.

  • Isolation from the host.

Containers that are not well isolated from the host may provide a pathway to attack the host. These risks may be from sharing the network and process namespaces with the host.

Some best practices you can implement in containerized environments to avoid the risks mentioned above include the following:

  1. Package a single application per container.

Since a container is designed to have the same lifespan as the application it hosts, each of your applications should run in its own containers. When the container stops, so does the application. Running multiple applications in one container may result in shutting down applications meant to continue running. In addition, having a health check on one of your applications may not be indicative of the overall container health.

2. Avoid running applications with a privileged flag.

Privileged containers create a considerable security risk that may easily wreak havoc if the container is compromised. As a best practice, you should implement the principle of least privilege, grant the container access only to trusted sources and conduct regular security audits.

3. Use multi-stage builds.

Multi-stage builds make it possible to build out an application; then remove any unnecessary development tools from the container. Multi-stage builds help you to keep all the dependencies needed during the build process; in an intermediate build stage. This way, your final image will not contain your dev tools and will be smaller in size.

4. Use trusted base images.

Building on top of untrusted or unmaintained images will inherit all the problems and vulnerabilities that come with that image. Best practices for base images include; using verified images over, images from unknown sources and using updated versions of the base image

5. Frequently update your images.

Images that are updated frequently tend to have patches for the recently discovered vulnerabilities. The best practices include; regularly checking for stable long-term releases.

6. Prevent sensitive information from leaking.

Sensitive data such as credentials, tokens, SSH keys, database names, connection strings and TLS certificates; may be required when running the application. It is bad practice to hardcode these values. If the application supports configuration via environment variables, use them to set the secrets on execution or use secrets manager capabilities to provide the values as environment variables.

7. Use fixed tags for mutability

Since tags can be changed, therefore, several images can probably have the same “latest” tag which may confuse automated builds. To avoid this, use more specific tags: such as the version: or the commit hash.
With these best practices in place, among others, you will be in a better position to improve the security posture of your environment. Implementing the best security practices is crucial, and we would be happy to discuss how best you can secure your containerized environment. So, book a call with us here, and we will certainly help.

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