Offline environments

It's possible to run most of the GitLab security scanners when not connected to the internet.

This document describes how to operate Secure Categories (that is, scanner types) in an offline environment. These instructions also apply to self-managed installations that are secured, have security policies (for example, firewall policies), or are otherwise restricted from accessing the full internet. GitLab refers to these environments as offline environments. Other common names include:

Air-gapped environments
Limited connectivity environments
Local area network (LAN) environments
Intranet environments

These environments have physical barriers or security policies (for example, firewalls) that prevent or limit internet access. These instructions are designed for physically disconnected networks, but can also be followed in these other use cases.

Defining offline environments

In an offline environment, the GitLab instance can be one or more servers and services that can communicate on a local network, but with no or very restricted access to the internet. Assume anything within the GitLab instance and supporting infrastructure (for example, a private Maven repository) can be accessed through a local network connection. Assume any files from the internet must come in through physical media (USB drive, hard drive, writeable DVD, etc.).

Overview

GitLab scanners usually connect to the internet to download the latest sets of signatures, rules, and patches. A few extra steps are necessary to configure the tools to function properly by using resources available on your local network.

Container registries and package repositories

At a high-level, the security analyzers are delivered as Docker images and may leverage various package repositories. When you run a job on an internet-connected GitLab installation, GitLab checks the GitLab.com-hosted container registry to check that you have the latest versions of these Docker images and possibly connect to package repositories to install necessary dependencies.

In an offline environment, these checks must be disabled so that GitLab.com isn't queried. Because the GitLab.com registry and repositories are not available, you must update each of the scanners to either reference a different, internally-hosted registry or provide access to the individual scanner images.

You must also ensure that your app has access to common package repositories that are not hosted on GitLab.com, such as npm, yarn, or Ruby gems. Packages from these repos can be obtained by temporarily connecting to a network or by mirroring the packages inside your own offline network.

Interacting with the vulnerabilities

Once a vulnerability is found, you can interact with it. Read more on how to interact with the vulnerabilities.

Please note that in some cases the reported vulnerabilities provide metadata that can contain external links exposed in the UI. These links might not be accessible within an offline environment.

Automatic remediation for vulnerabilities

The automatic remediation for vulnerabilities feature is available for offline Dependency Scanning and Container Scanning, but may not work depending on your instance's configuration. We can only suggest solutions, which are generally more current versions that have been patched, when we are able to access up-to-date registry services hosting the latest versions of that dependency or image.

Scanner signature and rule updates

When connected to the internet, some scanners reference public databases for the latest sets of signatures and rules to check against. Without connectivity, this is not possible. Depending on the scanner, you must therefore disable these automatic update checks and either use the databases that they came with and manually update those databases or provide access to your own copies hosted within your network.

Specific scanner instructions

Each individual scanner may be slightly different than the steps described above. You can find more information at each of the pages below:

Loading Docker images onto your offline host

To use many GitLab features, including security scans and Auto DevOps, the runner must be able to fetch the relevant Docker images.

The process for making these images available without direct access to the public internet involves downloading the images then packaging and transferring them to the offline host. Here's an example of such a transfer:

Download Docker images from public internet.
Package Docker images as tar archives.
Transfer images to offline environment.
Load transferred images into offline Docker registry.

Using the official GitLab template

GitLab provides a vendored template to ease this process.

This template should be used in a new, empty project, with a gitlab-ci.yml file containing:

include:
  - template: Secure-Binaries.gitlab-ci.yml

The pipeline downloads the Docker images needed for the Security Scanners and saves them as job artifacts or pushes them to the Container Registry of the project where the pipeline is executed. These archives can be transferred to another location and loaded in a Docker daemon. This method requires a runner with access to both gitlab.com (including registry.gitlab.com) and the local offline instance. This runner must run in privileged mode to be able to use the docker command inside the jobs. This runner can be installed in a DMZ or on a bastion, and used only for this specific project.

Scheduling the updates

By default, this project's pipeline runs only once, when the .gitlab-ci.yml is added to the repo. To update the GitLab security scanners and signatures, it's necessary to run this pipeline regularly. GitLab provides a way to schedule pipelines. For example, you can set this up to download and store the Docker images every week.

Some images can be updated more frequently than others. For example, the vulnerability database for Container Scanning is updated daily. To update this single image, create a new Scheduled Pipeline that runs daily and set SECURE_BINARIES_ANALYZERS to clair-vulnerabilities-db. Only this job is triggered, and the image is updated daily and made available in the project registry.

Using the secure bundle created

The project using the Secure-Binaries.gitlab-ci.yml template should now host all the required images and resources needed to run GitLab Security features.

Next, you must tell the offline instance to use these resources instead of the default ones on GitLab.com. To do so, set the environment variable SECURE_ANALYZERS_PREFIX with the URL of the project container registry.

You can set this variable in the projects' .gitlab-ci.yml, or in the GitLab UI at the project or group level. See the GitLab CI/CD environment variables page for more information.

Variables

The following table shows which variables you can use with the Secure-Binaries.gitlab-ci.yml template:

VARIABLE	Description	Default value
`SECURE_BINARIES_ANALYZERS`	Comma-separated list of analyzers to download	`"bandit, brakeman, gosec, and so on..."`
`SECURE_BINARIES_DOWNLOAD_IMAGES`	Used to disable jobs	`"true"`
`SECURE_BINARIES_PUSH_IMAGES`	Push files to the project registry	`"true"`
`SECURE_BINARIES_SAVE_ARTIFACTS`	Also save image archives as artifacts	`"false"`
`SECURE_BINARIES_ANALYZER_VERSION`	Default analyzer version (Docker tag)	`"2"`

Alternate way without the official template

If it's not possible to follow the above method, the images can be transferred manually instead:

Example image packager script

#!/bin/bash
set -ux

# Specify needed analyzer images
analyzers=${SAST_ANALYZERS:-"bandit eslint gosec"}
gitlab=registry.gitlab.com/gitlab-org/security-products/analyzers/

for i in "${analyzers[@]}"
do
  tarname="${i}_2.tar"
  docker pull $gitlab$i:2
  docker save $gitlab$i:2 -o ./analyzers/${tarname}
  chmod +r ./analyzers/${tarname}
done

Example image loader script

This example loads the images from a bastion host to an offline host. In certain configurations, physical media may be needed for such a transfer:

#!/bin/bash
set -ux

# Specify needed analyzer images
analyzers=${SAST_ANALYZERS:-"bandit eslint gosec"}
registry=$GITLAB_HOST:4567

for i in "${analyzers[@]}"
do
  tarname="${i}_2.tar"
  scp ./analyzers/${tarname} ${GITLAB_HOST}:~/${tarname}
  ssh $GITLAB_HOST "sudo docker load -i ${tarname}"
  ssh $GITLAB_HOST "sudo docker tag $(sudo docker images | grep $i | awk '{print $3}') ${registry}/analyzers/${i}:2"
  ssh $GITLAB_HOST "sudo docker push ${registry}/analyzers/${i}:2"
done

Using GitLab Secure with AutoDevOps in an offline environment

You can use GitLab AutoDevOps for Secure scans in an offline environment. However, you must first do these steps:

Load the container images into the local registry. GitLab Secure leverages analyzer container images to do the various scans. These images must be available as part of running AutoDevOps. Before running AutoDevOps, follow the above steps to load those container images into the local container registry.
Set the pipeline variable to ensure that AutoDevOps looks in the right place for those images. The AutoDevOps templates leverage the SECURE_ANALYZERS_PREFIX variable to identify the location of analyzer images. This variable is discussed above in Using the secure bundle created. Ensure that you set this variable to the correct value for where you loaded the analyzer images. You could consider doing this with a pipeline variable or by modifying the .gitlab-ci.yml file directly.

Once these steps are complete, GitLab has local copies of the Secure analyzers and is set up to use them instead of an Internet-hosted container image. This allows you to run Secure in AutoDevOps in an offline environment.

Note that these steps are specific to GitLab Secure with AutoDevOps. Using other stages with AutoDevOps may require other steps covered in the Auto DevOps documentation.