Strengthening Container Security Through Docker Image Vulnerability Scanning

Introduction

Docker has become a vital tool in containerization, simplifying the process of building, deploying, and managing applications. However, as Docker images contain all the components necessary to run an application, they can introduce security risks if software vulnerabilities or dependencies exist. A Docker image vulnerability scan helps identify and mitigate these risks, ensuring the security and integrity of applications in a containerized environment.

Docker Image

A Docker image is a self-contained package that includes everything needed to run a specific application. This package typically consists of the application code, system libraries, runtime environments, configuration files, and any dependencies required for the application to function. Docker images are essential for creating containers, which are lightweight, portable environments where applications run consistently across different systems.

Images are built from instructions in a Dockerfile, which defines the steps to assemble the image layer by layer. Each layer contains changes from the previous stage, such as installing a new library or configuring the system. Since these images are often reused and shared across environments, ensuring they are secure is important.

Vulnerability Scan

A vulnerability scan is a process used to identify potential security weaknesses in software, systems, or networks. These scans detect known vulnerabilities like outdated libraries, missing patches, or insecure configurations that attackers could exploit.

In the context of Docker, a vulnerability scan analyzes the components of a Docker image to identify potential security risks. These scans check for known vulnerabilities in the operating system, libraries, and other dependencies that comprise the image. Various tools, such as Trivy, Clair, Anchore, and Aqua Security, can perform these scans. After scanning, vulnerabilities are typically classified by severity (e.g., critical, high, medium, low) to help prioritize security fixes. Regularly performing vulnerability scans on Docker images ensures that applications remain secure and that potential risks are addressed before deployment to production.

Steps for Docker Vulnerability Scan

Step 1: SSH into your VM

Check for the running container by giving

In this VM, the WordPress application is running on a docker container.

Note: How to install WordPress, please refer to the document “Passing environment variable” in docker advanced Lab2

Image vulnerability scan with GCP API (Container Scanning API)

Steps to enable GCP API (Container Scanning API):-

1. Search APIs and Services in the search bar

2. Go to ENABLE APIS AND SERVICES

3. In the search bar enter Container Scanning API

4. Enable the API by clicking on the Enable API

5. Go to a container registry and, under settings, turn on scanning on.

Step 2: Tag the docker image that you want to push

Step 3: Go to the container registry and check for the pushed image where you can see all the vulnerabilities after the scanning

Step 4: To view vulnerabilities for an image tag or a layer

gcloud beta container images describe HOSTNAME/PROJECT_ID/IMAGE_ID@sha256:HASH Can you please provide me with access to this document?

–show-package-vulnerability

• HOSTNAME is the multi-regional hostname:
  • gcr.io
  • asia.gcr.io
  • eu.gcr.io
  • us.gcr.io
• PROJECT_ID is the ID of the project containing the images.
• IMAGE_ID is the ID of the image for which you want to view vulnerabilities.
• HASH is the image digest.

Step 5: Vulnerability using filter occurrences:

Conclusion

Regularly scanning Docker images for vulnerabilities helps safeguard applications and ensure they are deployed with security best practices in mind.

Drop a query if you have any questions regarding Docker image vulnerability scans and we will get back to you quickly.

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