Containers are commonly used in order to run and deploy the applications. But here is one thing that you need to consider: It sometimes becomes vulnerable to security threats. To protect your hardened container images from security threats, you need to follow some important tips that we have mentioned in this article. So keep reading!
Tip 1: Start with a Small Base Image
Container images are usually built with base images that contain lots of system files and libraries which makes them large in size. There are also possibilities that some extra software is also included in this. This extra software becomes the cause of security risks.
What to Do:
- Always try to choose a base image that is lightweight such as Alpine Linux or Distroless.
- Remove all the tools and dependencies that are not necessary.
- Don’t use general-purpose images that include extra software and go with the dedicated ones.
When the base image is smaller, it means there are fewer chances for security risks which leads to faster performance.
Tip 2: Scan Your Images for Security Issues
Security flaws in hardened container images can be exploited by attackers. That’s why scanning your images regularly is important.
What to Do:
- Use security scanning tools like Trivy, Clair, or Anchore.
- Fix vulnerabilities by updating outdated dependencies.
- Avoid using unverified or outdated images from public sources.
Regular scanning helps keep your container images safe from known security issues.
Tip 3: Run Containers as a Non-Root User
By default, many container images run as the root user, which is risky. If an attacker gains access, they could take full control.
What to Do:
- Create a separate non-root user for your container.
- Use the “USER” command in the Dockerfile to set a non-root user.
- Follow the principle of least privilege to limit permissions.
Running as a non-root user adds an extra layer of security.
Tip 4: Sign and Verify Your Container Images
Hackers can modify container images and add malicious code. To prevent this, signing and verifying images is essential.
What to Do:
- Use tools like Docker Content Trust (DCT) or Cosign to sign images.
- Verify images before downloading or deploying them.
- Store signed images in a trusted private registry.
Signing images ensures that only trusted images are used in your environment.
Tip 5: Restrict Network and File Access
Giving containers full access to the network or file system can lead to security risks. It’s best to limit access to only what’s needed.
What to Do:
- Use network policies to control incoming and outgoing traffic.
- Mount files and directories as read-only unless modifications are required.
- Use security tools like Seccomp and AppArmor to restrict permissions.
Limiting access helps protect sensitive data and reduces security risks.
Tip 6: Keep Your Images Updated and Remove Old Ones
Outdated container images can have security flaws that attackers can exploit. Keeping your images updated is a simple but effective security measure.
What to Do:
- Update container images regularly to apply security patches.
- Remove unused or outdated images from your system.
- Use automation tools like CI/CD pipelines to manage updates efficiently.
Updated images reduce vulnerabilities and keep your containers safe.
Conclusion
Securing container images is important for protecting your applications. By following the above-mentioned tips, you can easily build hardened container images that are more secure. So follow these tips to minimize the attack surface and keep your containerized applications safe. Start applying these security measures today!
