Introduction

This tutorial aims to guide you on how to use security tools to scan Docker images for vulnerabilities. We will cover the process of installing a security scanner, scanning your Docker images, and interpreting the results to identify and address any security risks.

By the end of this tutorial, you will learn:
- What Docker image scanning is and why it's important
- How to use a security tool to scan Docker images
- How to interpret and act on the scan results

Prerequisites:
- Basic understanding of Docker and Docker images
- Docker installed on your machine
- A Docker image to scan

Step-by-Step Guide

1. Choosing a Scanner:
   There are several open-source and commercial tools available for Docker image scanning, such as Clair, Trivy, Docker Bench, etc. Choose a tool that best fits your needs.

2. Installing the Scanner:
   Most scanners can be installed with a simple command-line instruction. For example, to install Trivy, you would use:
   $ curl -sfL https://raw.githubusercontent.com/aquasecurity/trivy/main/contrib/install.sh | sh -s -- -b /usr/local/bin

3. Scanning the Docker Image:
   Once the scanner is installed, you can scan an image. For example, with Trivy, you can scan an image using:
   $ trivy image [image name]

4. Interpreting the Results:
   The scan results will show a list of vulnerabilities found in your image. Each vulnerability is categorized based on its severity.

Code Examples

1. Installing Trivy:

bash # This command downloads and installs Trivy curl -sfL https://raw.githubusercontent.com/aquasecurity/trivy/main/contrib/install.sh | sh -s -- -b /usr/local/bin

1. Scanning a Docker Image:

bash # Replace [image name] with your Docker image name trivy image [image name]

This will output a list of vulnerabilities found in your Docker image.

Summary

In this tutorial, we learned about Docker image scanning, installed a security scanner (Trivy), and used it to scan a Docker image. We also discussed how to interpret the scan results.

To continue your learning, you can explore:
- How to fix the vulnerabilities found in your Docker image
- How to automate Docker image scanning in your CI/CD pipeline

Practice Exercises

1. Exercise 1: Install a different security scanner (like Clair) and scan the same Docker image. Compare the results with Trivy.
2. Exercise 2: Scan a different Docker image and interpret the results. Try to fix some of the vulnerabilities found.
3. Exercise 3: Automate the Docker image scanning process by integrating it into your CI/CD pipeline.

Tips for further practice

• Scanning Docker images should be a regular process in your workflow. Try to automate this process as much as possible.
• Always keep your security scanner updated to catch the latest vulnerabilities.
• Don't just rely on scanners. Follow best practices when creating your Docker images to minimize vulnerabilities.