A practical guide to writing secure Dockerfiles

Your Dockerfile is a critical form of infrastructure as code. Learn to write secure, minimal images and automate security checks before deployment.

#1about 2 minutes

Why Dockerfile security is a critical foundation

Dockerfiles act as the blueprint for container images, making their security essential for preventing supply chain attacks and infrastructure compromise.

#2about 5 minutes

Following official Docker best practices for images

Start with small base images, use multi-stage builds, and manage the build context with a .dockerignore file to create efficient and secure containers.

#3about 4 minutes

Advanced security practices for hardening Dockerfiles

Enhance security by running containers as a non-root user, using COPY instead of ADD, avoiding hardcoded secrets, and pulling from trusted image registries.

#4about 4 minutes

Using Docker BuildKit to handle secrets securely

Docker's BuildKit allows mounting secrets and forwarding SSH agents during the build process, preventing sensitive credentials from being stored in image layers.

#5about 5 minutes

Automating checks with linters like Hadolint and Dockle

Use automated linters like Hadolint for best practices and Dockle for CIS benchmark compliance to enforce security standards in your CI/CD pipeline.

#6about 2 minutes

Reducing attack surface with Docker-slim

Docker-slim minifies container images by removing unnecessary files and can automatically generate seccomp and AppArmor profiles to harden runtime security.

#7about 3 minutes

Analyzing image layers for security with Dive

The Dive tool provides a layer-by-layer inspection of a Docker image, helping to identify inefficiencies and potential security risks like backdoors.

#8about 4 minutes

Introducing Open Policy Agent for custom policies

Open Policy Agent (OPA) and its language Rego provide a general-purpose engine for enforcing custom, organization-specific security policies on structured data like Dockerfiles.

#9about 6 minutes

Writing custom Dockerfile policies with Conftest

Leverage Conftest to write and apply custom Rego policies that validate Dockerfiles against specific organizational rules, such as only allowing images from a trusted private registry.

#10about 2 minutes

Next steps for implementing Dockerfile security

Implement security best practices early using linters in your IDE, integrate automated checks into CI/CD pipelines, and create standardized custom policies for your organization.