Why container security matters in Docker - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why is container security important?

Containers share the host OS kernel. What risk does this create if a container is compromised?

A The attacker can only access that container's files and nothing else.

B The attacker can potentially access the host system and other containers.

C The container will automatically shut down to prevent damage.

D The container will lose network connectivity but remain running.

💡 Hint

Think about what sharing the OS kernel means for isolation.

Because containers share the host OS kernel, if one container is compromised, an attacker might escape the container and access the host or other containers. This is why container security is critical.

💻 Command Output

intermediate

Output of scanning a vulnerable Docker image

What output will the following command produce when scanning an image with known vulnerabilities?

docker scan alpine:3.12

Docker

docker scan alpine:3.12

A Vulnerabilities found with severity levels and fix suggestions.

B No vulnerabilities found. Image is secure.

C Syntax error: 'scan' is not a valid docker command.

D Image not found error.

💡 Hint

Docker scan uses vulnerability databases to check images.

The 'docker scan' command checks images for known vulnerabilities and reports severity and fixes if any are found.

❓ Configuration

advanced

Configuring Docker to run containers with least privilege

Which Docker run option helps improve container security by limiting privileges?

A docker run --read-only alpine

B docker run --network=host alpine

C docker run --privileged alpine

D docker run --rm alpine

💡 Hint

Think about restricting write access inside the container.

The '--read-only' flag makes the container's filesystem read-only, reducing risk by preventing writes and limiting damage if compromised.

❓ Troubleshoot

advanced

Troubleshooting a container escape vulnerability

A container runs with '--privileged' flag and an attacker escapes to the host. What is the main cause?

A The container was using a read-only filesystem.

B The container was missing environment variables.

C The container image was too large.

D The container was running with too many privileges.

💡 Hint

Consider what '--privileged' does to container permissions.

The '--privileged' flag gives the container extended permissions, increasing risk of container escape and host compromise.

✅ Best Practice

expert

Best practice to reduce container image vulnerabilities

Which practice best reduces vulnerabilities in container images?

A Install all packages and tools inside the image for flexibility.

B Run containers as root user for easier management.

C Use minimal base images and regularly update them.

D Disable image scanning to speed up deployment.

💡 Hint

Think about minimizing attack surface and keeping software current.

Using minimal base images reduces unnecessary software that can have vulnerabilities. Regular updates patch known security issues.