Getting Started: Stub and Harden a Container Image with Docker and GitLab

Use the RapidFort Command Line Interface (CLI) tools to stub and harden a container image with Docker and GitLab
Prerequisites
You will need the following:
RapidFort Server (SaaS or On-Premises)
RapidFort Service Account
For more information on RapidFort service accounts, please visit RapidFort Service Accounts​
GitLab Runner
The GitLab Runner must meet the minimum requirements for installing the RapidFort Command Line Interface Tools​
Deployment Environment (for example, Kubernetes, Docker, Docker-Compose, AWS Fargate)
The deployment environment must have HTTPS access to the RapidFort server
The deployment environment must provide support for adding the SYS_PTRACE Linux kernel capability
In this tutorial, we will deploy and test the stub image on the GitLab runner
Container Registry (for example, Amazon Elastic Container Registry, Docker Hub, Microsoft Azure Container Registry, and so forth)
In this tutorial, we will not push images to a container registry
Stub, Test, and Harden the NGINX Docker Image
In this tutorial, we will stub, test, and harden the NGINX Docker image.
Original Image: The NGINX Docker image available directly from Docker Hub. The original image has not yet been optimized and secured by RapidFort and may have known vulnerabilities.
Stub Image: The original image with additional dependencies necessary for RapidFort to trace the runtime behavior.
Hardened Image: The optimized and secured image generated by RapidFort.
Download the sample .gitlab-ci.yml file.
Update the following variables:
RF_ROOT_URL: 
For SaaS users, specify https://frontrow.rapidfort.com.
For On-Premises users, specify the hostname or IP address of your RapidFort on-premises server (for example, https://rapidfort.example.com).
RF_ACCESS_ID: Specify the access id for your RapidFort service account.
RF_SECRET_ACCESS_KEY: Specify the secret access key for your RapidFort service account.
RF_CLI_UPDATE: Specify "no" to download and install the RapidFort CLI tools only if they are not already installed on the runner or "yes" to always download and install the tools (even if they are already installed).
RF_CLI_PATH: Specify the location where the RapidFort CLI tools will be installed on the GitLab runner.
We recommend adding these as environment variables.
.gitlab-ci.yml
variables:
  DOCKER_IMAGE_NAME: "nginx"
  TAG: latest
  RF_ROOT_URL: https://frontrow.rapidfort.com
  # generate service account & replace these
  RF_ACCESS_ID: RFabcdefghijkl123456
  RF_SECRET_ACCESS_KEY: 01234567891011abcdefghijklmnopqrstuvwxyz
  RF_CLI_UPDATE: "no"
  RF_CLI_PATH: /home/gitlab-runner/.local/bin
​
default:
  tags:
    - ubuntu
  before_script:
    - |
      if [ -z "$(command -v rflogin)" ] || [ "${RF_CLI_UPDATE}" == "yes" ]; then
        curl -ks "${RF_ROOT_URL}"/cli/ | bash
      fi
      export PATH="$RF_CLI_PATH:$PATH"
​
stages:
  - Build
  - Stub
  - Deploy
  - Test
  - Harden
​
build:
  stage: Build
  script:
    - |
      docker pull $DOCKER_IMAGE_NAME:$TAG
      docker tag $DOCKER_IMAGE_NAME:$TAG $DOCKER_IMAGE_NAME:$TAG-$CI_PIPELINE_ID
​
generate-stub:
  stage: Stub
  script:
    - |
      # ** GENERATE STUB **
      rfstub $DOCKER_IMAGE_NAME:$TAG-$CI_PIPELINE_ID
      docker images | grep $DOCKER_IMAGE_NAME | grep $CI_PIPELINE_ID
​
deploy:
  stage: Deploy
  script:
    - |
      # Run & test stub
      docker run --rm --name $DOCKER_IMAGE_NAME-$TAG-$CI_PIPELINE_ID -p9999:80 --cap-add=SYS_PTRACE -d $DOCKER_IMAGE_NAME:$TAG-$CI_PIPELINE_ID-rfstub
​
test:
  stage: Test
  script:
    - |
      STATUS_CODE=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:9999 || /bin/true)
      until [ "${STATUS_CODE}" == 200 ]; do
        sleep 1
        STATUS_CODE=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:9999 || /bin/true)
      done
      # Load test
      ab -n 10 -c 10 http://localhost:9999/
      # Remove running stub
      docker stop $DOCKER_IMAGE_NAME-$TAG-$CI_PIPELINE_ID
​
Harden:
  stage: Harden
  script:
    - |
      # ** GENERATE HARDENED IMAGE **
      rfharden $DOCKER_IMAGE_NAME:$TAG-$CI_PIPELINE_ID-rfstub && echo "Hardened Done" || echo "Hardened Failed"
      docker images | grep $DOCKER_IMAGE_NAME | grep $CI_PIPELINE_ID
  when: manual
Stub
During the Stub stage, run rfstub to generate a stub image.
In this tutorial, we will not push the stub image to a container registry, but your pipeline will need to do so.
When you generate a stub image, RapidFort also scans the original image for packages and known vulnerabilities and computes the estimated risk reduction opportunity if the image is hardened. You may optionally visit the RapidFort dashboard to view the vulnerabilities and packages that were found in the original image.
Deploy and Test
Next, deploy and test the stub image so that RapidFort can trace the runtime behavior of the application and build the runtime profile.
The SYS_PTRACE Linux kernel capability must be added when deploying stub images so that RapidFort can trace the runtime behavior.
If you are planning to deploy the stub image in a Kubernetes environment, you will need to allow privilege escalation and read/write access to the root filesystem:
allowPrivilegeEscalation: true
readOnlyRootFilesystem: false
Make sure that your deployment environment (in this tutorial, the GitLab runner) allows HTTPS access to the RapidFort server.
Verify that Tracing Information is Propagated to the RapidFort Server
Log into the RapidFort dashboard. You should see an image list.
Select the image that you deployed.
In the left column, select Logs. Verify that the Logs table contains tracing information. You should see file accesses, system calls, and so forth. The Logs table contents are updated in real time.
If the Logs table is empty, please verify the following:
The stub image (not the original image) was deployed
The deployment configuration added the SYS_PTRACE Linux kernel capability
For Kubernetes environments, the deployment configuration allows privilege escalation and enable read/write access for the root filesystem
allowPrivilegeEscalation: true
readOnlyRootFilesystem: false
The environment in which the stub image was deployed has HTTPS access to the RapidFort server
If there are any issues, please update your deployment configuration and environment and deploy the stub image again. RapidFort cannot harden an image unless it has a valid runtime profile.
Harden
After you have deployed and tested the stub image and verified that the runtime profile information was propagated to RapidFort, you are ready to harden it.
Note that the Harden stage is manual. You must deploy and test the stub image and verify that the runtime profile was generated successfully before hardening it.
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Last modified 2mo ago