20 Container Security Interview Questions and Answers

As the world increasingly moves towards containerized applications, it’s important for security professionals to understand the ins and outs of container security. In a container security interview, you’ll likely be asked questions about the various security risks and challenges associated with containers, as well as how to mitigate those risks.

In this article, we’ll go over some of the most common container security interview questions and how you can answer them.

Container Security Interview Questions and Answers

Here are 20 commonly asked Container Security interview questions and answers to prepare you for your interview:

1. What is container security?

Container security is the security of the software containers that are used to run applications. Containers are a type of virtualization that allow for isolated execution of applications. This isolation is important for security, as it prevents one application from being able to access the resources of another.

2. Can you explain the history of containers?

The history of containers can be traced back to the early days of computing, when mainframes were the norm and each application ran in its own isolated environment. This approach was later adopted by Unix systems, which used “chroot” jails to isolate applications from each other. The modern concept of containers was popularized by Linux, which introduced “cgroups” to further isolate applications from each other and allow them to share resources more efficiently.

3. How can a Docker image be secured?

There are a few ways to secure a Docker image. One is to use a tool like CoreOS Clair to scan for vulnerabilities in the image. Another is to use a private registry like Quay.io, which provides additional security features like image signing and role-based access control. Finally, you can also use a tool like Docker Bench for Security to check for common security issues in Docker images.

4. Can you give me some examples of tools that can be used to enhance container security?

There are a number of tools that can be used to enhance container security, including:

– Container scanning tools, which can help identify vulnerabilities in container images
– Runtime security tools, which can help monitor and protect containers during runtime
– Configuration management tools, which can help ensure that containers are properly configured
– Network security tools, which can help secure the communication between containers

5. What are the main reasons why companies adopt containers and Kubernetes?

The main reasons companies adopt containers and Kubernetes are to improve their application development process and to improve the security of their applications. Containers and Kubernetes help to isolate applications from each other and from the underlying infrastructure, which makes it easier to develop and deploy applications. In addition, containers and Kubernetes make it easier to patch and update applications, which can help to improve security.

6. What are namespaces in Linux and how do they impact container security?

Namespaces are a Linux kernel feature that allows for complete isolation between different processes running on a system. This means that each process can have its own private view of the system, including its own file system, network, and process ID space. This isolation is what allows containers to be so secure, because it is very difficult for an attacker to escape from a container if they are not able to access the other processes running on the system.

7. How can you use SELinux for enhancing container security?

SELinux is a great way to add an extra layer of security to your containers. By using SELinux, you can control which processes inside of a container can access which files and resources. This can help to prevent malicious processes from accessing sensitive data or wreaking havoc on your system.

8. What’s the difference between the various types of host volume mounts available with Docker? What type would you recommend under what circumstances and why?

There are three types of host volume mounts available with Docker: bind mounts, named volumes, and anonymous volumes.

Bind mounts are the most basic type of host volume mount, and simply mount a file or directory from the host into the container. This type of mount is easy to use and understand, but has some limitations. First, bind mounts can only be used with files and directories that already exist on the host. Second, bind mounts can only be used with a single container at a time. Finally, bind mounts can be difficult to manage at scale.

Named volumes are a bit more sophisticated than bind mounts, and allow for the creation of named volumes that can be used by multiple containers simultaneously. Named volumes also have the advantage of being easier to manage than bind mounts, since they can be created and destroyed using simple commands. However, named volumes can only be used with a single host at a time.

Anonymous volumes are the most sophisticated type of host volume mount, and allow for the creation of anonymous volumes that can be used by multiple containers simultaneously. Anonymous volumes have the advantage of being easier to manage than both bind mounts and named volumes, since they can be created and destroyed using simple commands. However, anonymous volumes can only be used with a single host at a time.

9. What are the features of cgroups, namespaces, and capabilities implemented by default in Docker?

Cgroups allow for resource isolation and management within a container, namespaces provide a private view of the system for a container, and capabilities allow for granular control over what a container can do. By default, Docker containers have access to all cgroups, namespaces, and capabilities.

10. What are the main differences between Docker and LXC?

LXC is an operating system-level virtualization method for running multiple isolated Linux systems (containers) on a single control host. Docker is a tool that allows developers to easily package their applications and dependencies into a self-contained unit called a container. Containers are then run on top of a Linux operating system using the Docker runtime.

11. What are the different ways to secure Docker containers?

There are a few different ways to secure Docker containers. One way is to use a tool like AppArmor or SELinux to restrict the actions that a container can perform. Another way is to use a tool like a container firewall to control traffic going in and out of a container. Finally, you can also use encryption to protect the data inside a container.

12. Why does every process in a container have its own PID namespace?

One of the key security features of containers is that they isolate processes from each other. By giving each process its own PID namespace, it becomes much more difficult for processes to interfere with each other, as they are effectively running in their own separate universes. This helps to keep the overall system more secure, as one compromised process is less likely to be able to take down the entire system.

13. Do you need root privileges to run a container on your machine? Why or why not?

No, you do not need root privileges to run a container on your machine. The whole point of containers is that they are isolated from the rest of the system, so they can be run without root privileges. This isolation also makes them more secure, since any vulnerabilities in the container will not be able to affect the rest of the system.

14. What is AppArmor and how does it help with securing containers?

AppArmor is a security module for the Linux kernel that helps to restrict the capabilities of applications running inside of containers. By doing so, it helps to prevent malicious or accidental damage to the host system.

15. What is the purpose of the docker-bench tool? How can it help improve the security posture of our applications?

The docker-bench tool is used to perform a series of tests against a Docker host in order to identify any potential security issues. These tests cover a wide range of topics, including host configuration, container configuration, and runtime security. By running this tool and addressing any issues that are identified, we can help improve the overall security posture of our applications.

16. Can you explain “Dockerfiles” and their importance in containerization?

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.

17. What are the best practices you should follow when building Docker images?

There are a few best practices you should follow when building Docker images:

1. Use a minimal base image – using a minimal base image will help reduce the size of your final image and also reduce the attack surface.
2. Don’t install unnecessary packages – only install the packages that are absolutely necessary for your application to run.
3. Keep your image up to date – regularly update your base image and any packages that you have installed.
4. Use a trusted source for your base image – only use base images from trusted sources.
5. Use a non-root user – running your application as a non-root user will help reduce the potential for privilege escalation attacks.

18. What are the key components of an effective container security strategy?

There are a few key components to an effective container security strategy. First, you need to have a clear understanding of your environment and what you are trying to protect. Second, you need to have a strong foundation in place for image security and container runtime security. Finally, you need to have a plan in place for monitoring and responding to security incidents.

19. What role does DevOps play in ensuring container security?

DevOps is responsible for ensuring that containers are properly configured and secured before they are deployed. This includes ensuring that the container images are free from vulnerabilities, that the containers are properly isolated from each other and the host system, and that the containers are properly configured to communicate with each other.

20. What are the advantages of using third party container registries like Quay over other options like DockerHub?

There are several advantages to using a third party container registry like Quay over other options like DockerHub. First, Quay offers more security features than DockerHub, making it a better option for storing sensitive data. Quay also offers more control over who has access to your images, and can provide additional features like image signing and vulnerability scanning. Finally, Quay’s support for multiple platforms makes it a more versatile option than DockerHub.