Everything runs in containers these days. How do we make sure container images are safe?
It's so true – these days, everything runs in containers. From microservices to serverless applications, containers are everywhere. And with good reason – they're lightweight, portable, and easy to deploy. But with all the benefits that containers bring, one big question needs to be answered: how do we ensure that container images are safe?
There are a few different ways to approach this problem.
- Use CLI First to Check Images
Use the command line interface (CLI) to check images before running them. By using the 'docker inspect' command, you can see all the information about a particular image, including the history of that image.
- Automate the process of scanning using CI Pipeline
By automating the scanning of your images as part of your continuous integration (CI) pipeline, you can ensure that only safe images are deployed to your production environment.
- Cache your scan results
Caching your scan results can help speed up the scanning process since you won't have to scan images you've already scanned and confirmed as safe.
- Use Docker Hub's vulnerability scanning feature
Using Docker Hub to store your images, you can take advantage of its vulnerability scanning feature. This feature scans your images for known vulnerabilities and alerts you if any are found.
- Ensure to choose the right sized image for your application
It's important to choose the right-sized image for your application. If you use too small an image, you might not have all the dependencies your application needs. On the other hand, using a too large image will make your application unnecessarily big and slow to download.
- Use a multi-stage build when possible
A multi-stage build is a way to create a Docker image in multiple stages, with each stage using a different base image. It can be useful for creating images that are smaller and more secure. You can start with a large base image (such as Debian or Ubuntu) that has all the tools you need to build your application and then create a second stage that contains only your built application and its dependencies.
- Scan for secrets and other sensitive data in your images
Before you push your images to a registry, you should always scan them for secrets and other sensitive data. Several tools available can help you with this and they give you a report of any secrets or sensitive data they find in your images.
Of course, security is an ongoing process, and as new threats arise, you'll need to adapt your approach accordingly. But by following these principles, you'll be well on your way to building secure Docker images that will help keep your applications and data safe.