• Authenticate to a remote registry

Container Scanning

Your application’s Docker image may itself be based on Docker images that contain known vulnerabilities. By including an extra Container Scanning job in your pipeline that scans for those vulnerabilities and displays them in a merge request, you can use GitLab to audit your Docker-based apps.

For an overview, see Container Scanning .

Container Scanning is often considered part of Software Composition Analysis (SCA). SCA can contain aspects of inspecting the items your code uses. These items typically include application and system dependencies that are almost always imported from external sources, rather than sourced from items you wrote yourself.

GitLab offers both Container Scanning and Dependency Scanning to ensure coverage for all of these dependency types. To cover as much of your risk area as possible, we encourage you to use all of our security scanners.

Overview

GitLab integrates with open-source tools for vulnerability static analysis in containers:

• Trivy
• Grype

To integrate GitLab with security scanners other than those listed here, see Security scanner integration .

You can enable container scanning by doing one of the following:

Include the CI job in your existing .gitlab-ci.yml file.
• Implicitly use Auto Container Scanning , provided by Auto DevOps .

GitLab compares the found vulnerabilities between the source and target branches, and shows the information directly in the merge request.

Capabilities CapabilityIn FreeIn Ultimate Configure Scanners YesYes Customize Settings ( Variables , Overriding , offline environment support , etc)YesYes View JSON Report as a CI job artifactYesYes Generation of a JSON report of dependencies as a CI job artifactYesYes Ability to enable container scanning via an MR in the GitLab UIYesYes UBI Image Support YesYes Support for TrivyYesYes Support for GrypeYesYes Inclusion of GitLab Advisory DatabaseLimited to the time-delayed content from GitLab advisories-communities projectYes - all the latest content from Gemnasium DB Presentation of Report data in Merge Request and Security tab of the CI pipeline jobNoYes Interaction with Vulnerabilities such as merge request approvalsNoYes Solutions for vulnerabilities (auto-remediation) NoYes Support for the vulnerability allow list NoYes Access to Security Dashboard page NoYes Access to Dependency List page NoYes

Prerequisites

To enable container scanning in your pipeline, you need the following:

• GitLab CI/CD pipeline must include the test stage, which is available unless overridden with the stages keyword.
• GitLab Runner with the docker or kubernetes executor on Linux/amd64.
• Docker 18.09.03 or later installed on the same computer as the runner. If you’re using the shared runners on GitLab.com, then this is already the case.
• An image matching the supported distributions .
• Build and push the Docker image to your project’s container registry.
• If you’re using a third-party container registry, you might need to provide authentication credentials through the CS_REGISTRY_USER and CS_REGISTRY_PASSWORD configuration variables . For more details on how to use these variables, see authenticate to a remote registry .

Configuration

To enable container scanning, add the Container-Scanning.gitlab-ci.yml template to your .gitlab-ci.yml file:

include:
  - template: Security/Container-Scanning.gitlab-ci.yml

The included template:

• Creates a container_scanning job in your CI/CD pipeline.
• Pulls the built Docker image from your project’s container registry (see prerequisites ) and scans it for possible vulnerabilities.

GitLab saves the results as a Container Scanning report artifact that you can download and analyze later. When downloading, you always receive the most-recent artifact. If dependency scan is enabled , a Dependency Scanning report artifact is also created.

The following is a sample .gitlab-ci.yml that builds your Docker image, pushes it to the container registry, and scans the image:

include:
  - template: Jobs/Build.gitlab-ci.yml
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    CS_DEFAULT_BRANCH_IMAGE: $CI_REGISTRY_IMAGE/$CI_DEFAULT_BRANCH:$CI_COMMIT_SHA

Setting CS_DEFAULT_BRANCH_IMAGE avoids duplicate vulnerability findings when an image name differs across branches. The value of CS_DEFAULT_BRANCH_IMAGE indicates the name of the scanned image as it appears on the default branch. For more details on how this deduplication is achieved, see Setting the default branch image .

Customizing the container scanning settings

There may be cases where you want to customize how GitLab scans your containers. For example, you may want to enable more verbose output, access a Docker registry that requires authentication, and more. To change such settings, use the variables parameter in your .gitlab-ci.yml to set CI/CD variables . The variables you set in your .gitlab-ci.yml overwrite those in Container-Scanning.gitlab-ci.yml .

This example includes the container scanning template and enables verbose output for the analyzer:

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
variables:
    SECURE_LOG_LEVEL: 'debug'

Scan an image in a remote registry

To scan images located in a registry other than the project’s, use the following .gitlab-ci.yml :

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    CS_IMAGE: example.com/user/image:tag

Authenticate to a remote registry

Scanning an image in a private registry requires authentication. Provide the username in the CS_REGISTRY_USER variable, and the password in the CS_REGISTRY_PASSWORD configuration variable.

For example, to scan an image from AWS Elastic Container Registry:

container_scanning:
  before_script:
    - ruby -r open-uri -e "IO.copy_stream(URI.open('https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip'), 'awscliv2.zip')"
    - unzip awscliv2.zip
    - sudo ./aws/install
    - aws --version
    - export AWS_ECR_PASSWORD=$(aws ecr get-login-password --region region)
include:
  - template: Security/Container-Scanning.gitlab-ci.yml
variables:
    CS_IMAGE: <aws_account_id>.dkr.ecr.<region>.amazonaws.com/<image>:<tag>
    CS_REGISTRY_USER: AWS
    CS_REGISTRY_PASSWORD: "$AWS_ECR_PASSWORD"

Authenticating to a remote registry is not supported when FIPS mode is enabled.

Dependency list

Introduced in GitLab 14.6.

The CS_DISABLE_DEPENDENCY_LIST CI/CD variable controls whether the scan creates a Dependency List report. This variable is currently only supported when the trivy analyzer is used. The variable’s default setting of "false" causes the scan to create the report. To disable the report, set the variable to "true" :

For example:

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    CS_DISABLE_DEPENDENCY_LIST: "true"

Report language-specific findings

Introduced in GitLab 14.6.

The CS_DISABLE_LANGUAGE_VULNERABILITY_SCAN CI/CD variable controls whether the scan reports findings related to programming languages. The languages supported depend on the scanner used :

Trivy .
• Grype .

By default, the report only includes packages managed by the Operating System (OS) package manager (for example, yum , apt , apk , tdnf ). To report security findings in non-OS packages, set CS_DISABLE_LANGUAGE_VULNERABILITY_SCAN to "false" :

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    CS_DISABLE_LANGUAGE_VULNERABILITY_SCAN: "false"

When you enable this feature, you may see duplicate findings in the Vulnerability Report if Dependency Scanning is enabled for your project. This happens because GitLab can’t automatically deduplicate findings across different types of scanning tools. Reference this comparison between GitLab Dependency Scanning and Container Scanning for more details on which types of dependencies are likely to be duplicated.

Available CI/CD variables

You can configure analyzers by using the following CI/CD variables.

All customization of GitLab security scanning tools should be tested in a merge request before merging these changes to the default branch. Failure to do so can give unexpected results, including a large number of false positives.

CI/CD Variable	Default	Description	Scanner
ADDITIONAL_CA_CERT_BUNDLE	""	Bundle of CA certs that you want to trust. See Using a custom SSL CA certificate authority for more details.	All
CI_APPLICATION_REPOSITORY	$CI_REGISTRY_IMAGE/$CI_COMMIT_REF_SLUG	Docker repository URL for the image to be scanned.	All
CI_APPLICATION_TAG	$CI_COMMIT_SHA	Docker repository tag for the image to be scanned.	All
CS_ANALYZER_IMAGE	registry.gitlab.com/security-products/container-scanning:6	Docker image of the analyzer.	All
CS_DEFAULT_BRANCH_IMAGE	""	The name of the CS_IMAGE on the default branch. See Setting the default branch image for more details. Introduced in GitLab 14.5.	All
CS_DISABLE_DEPENDENCY_LIST	"false"	Disable Dependency Scanning for packages installed in the scanned image. Introduced in GitLab 14.6.	All
CS_DISABLE_LANGUAGE_VULNERABILITY_SCAN	"true"	Disable scanning for language-specific packages installed in the scanned image. Introduced in GitLab 14.6.	All
CS_DOCKER_INSECURE	"false"	Allow access to secure Docker registries using HTTPS without validating the certificates.	All
CS_IMAGE_SUFFIX	""	Suffix added to CS_ANALYZER_IMAGE . If set to -fips , FIPS-enabled image is used for scan. See FIPS-enabled images for more details. Introduced in GitLab 14.10.	All
CS_IGNORE_UNFIXED	"false"	Ignore vulnerabilities that are not fixed.	All
CS_REGISTRY_INSECURE	"false"	Allow access to insecure registries (HTTP only). Should only be set to true when testing the image locally. Works with all scanners, but the registry must listen on port 80/tcp for Trivy to work.	All
CS_SEVERITY_THRESHOLD	UNKNOWN	Severity level threshold. The scanner outputs vulnerabilities with severity level higher than or equal to this threshold. Supported levels are UNKNOWN , LOW , MEDIUM , HIGH , and CRITICAL .	Trivy
CS_IMAGE	$CI_APPLICATION_REPOSITORY:$CI_APPLICATION_TAG	The Docker image to be scanned. If set, this variable overrides the $CI_APPLICATION_REPOSITORY and $CI_APPLICATION_TAG variables.	All
CS_REGISTRY_PASSWORD	$CI_REGISTRY_PASSWORD	Password for accessing a Docker registry requiring authentication. The default is only set if $CS_IMAGE resides at $CI_REGISTRY . Not supported when FIPS mode is enabled.	All
CS_REGISTRY_USER	$CI_REGISTRY_USER	Username for accessing a Docker registry requiring authentication. The default is only set if $CS_IMAGE resides at $CI_REGISTRY . Not supported when FIPS mode is enabled.	All
CS_DOCKERFILE_PATH	Dockerfile	The path to the Dockerfile to use for generating remediations. By default, the scanner looks for a file named Dockerfile in the root directory of the project. You should configure this variable only if your Dockerfile is in a non-standard location, such as a subdirectory. See Solutions for vulnerabilities for more details.	All
CS_QUIET	""	If set, this variable disables output of the vulnerabilities table in the job log. Introduced in GitLab 15.1.	All
SECURE_LOG_LEVEL	info	Set the minimum logging level. Messages of this logging level or higher are output. From highest to lowest severity, the logging levels are: fatal , error , warn , info , debug . Introduced in GitLab 13.1.	All

Supported distributions

Support depends on which scanner is used:

Distribution	Grype	Trivy
Alma Linux		✅
Alpine Linux	✅	✅
Amazon Linux	✅	✅
BusyBox	✅
CentOS	✅	✅
CBL-Mariner		✅
Debian	✅	✅
Distroless	✅	✅
Oracle Linux	✅	✅
Photon OS		✅
Red Hat (RHEL)	✅	✅
Rocky Linux		✅
SUSE		✅
Ubuntu	✅	✅

FIPS-enabled images

Introduced in GitLab 14.1.

GitLab also offers FIPS-enabled Red Hat UBI versions of the container-scanning images. You can therefore replace standard images with FIPS-enabled images. To configure the images, set the CS_IMAGE_SUFFIX to -fips or modify the CS_ANALYZER_IMAGE variable to the standard tag plus the -fips extension.

Scanner name	CS_ANALYZER_IMAGE
Default (Trivy)	registry.gitlab.com/security-products/container-scanning:6-fips
Grype	registry.gitlab.com/security-products/container-scanning/grype:6-fips
Trivy	registry.gitlab.com/security-products/container-scanning/trivy:6-fips

Prior to GitLab 15.0, the -ubi image extension is also available. GitLab 15.0 and later only support -fips .

Starting with GitLab 14.10, -fips is automatically added to CS_ANALYZER_IMAGE when FIPS mode is enabled in the GitLab instance.

Container scanning of images in authenticated registries is not supported when FIPS mode is enabled. When CI_GITLAB_FIPS_MODE is "true" , and CS_REGISTRY_USER or CS_REGISTRY_PASSWORD is set, the analyzer exits with an error and does not perform the scan.

Enable Container Scanning through an automatic merge request

Introduced in GitLab 14.9.

To enable Container Scanning in a project, create a merge request from the Security Configuration page:

1. In the project where you want to enable Container Scanning, go to Security and Compliance > Security configuration .
2. In the Container Scanning row, select Configure with a merge request .

This automatically creates a merge request with the changes necessary to enable Container Scanning. To complete the configuration, review and merge this merge request.

The configuration tool works best with no existing .gitlab-ci.yml file, or with a minimal configuration file. If you have a complex GitLab configuration file, it may not be parsed successfully and an error may occur.

Overriding the container scanning template

If you want to override the job definition (for example, to change properties like variables ), you must declare and override a job after the template inclusion, and then specify any additional keys.

This example sets GIT_STRATEGY to fetch :

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    GIT_STRATEGY: fetch

Change scanners

The container-scanning analyzer can use different scanners, depending on the value of the CS_ANALYZER_IMAGE configuration variable.

The following options are available:

Scanner name	CS_ANALYZER_IMAGE
Default ( Trivy )	registry.gitlab.com/security-products/container-scanning:6
Grype	registry.gitlab.com/security-products/container-scanning/grype:6
Trivy	registry.gitlab.com/security-products/container-scanning/trivy:6

Setting the default branch image

Introduced in GitLab 14.5.

By default, container scanning assumes that the image naming convention stores any branch-specific identifiers in the image tag rather than the image name. When the image name differs between the default branch and the non-default branch, previously-detected vulnerabilities show up as newly detected in merge requests.

When the same image has different names on the default branch and a non-default branch, you can use the CS_DEFAULT_BRANCH_IMAGE variable to indicate what that image’s name is on the default branch. GitLab then correctly determines if a vulnerability already exists when running scans on non-default branches.

As an example, suppose the following:

• Non-default branches publish images with the naming convention $CI_REGISTRY_IMAGE/$CI_COMMIT_BRANCH:$CI_COMMIT_SHA .
• The default branch publishes images with the naming convention $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .

In this example, you can use the following CI/CD configuration to ensure that vulnerabilities aren’t duplicated:

include:
  - template: Security/Container-Scanning.gitlab-ci.yml
container_scanning:
  variables:
    CS_DEFAULT_BRANCH_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
  before_script:
    - export CS_IMAGE="$CI_REGISTRY_IMAGE/$CI_COMMIT_BRANCH:$CI_COMMIT_SHA"
      if [ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]; then
        export CS_IMAGE="$CI_REGISTRY_IMAGE:$CI_COMMIT_SHA"

CS_DEFAULT_BRANCH_IMAGE should remain the same for a given CS_IMAGE . If it changes, then a duplicate set of vulnerabilities are created, which must be manually dismissed.

When using Auto DevOps , CS_DEFAULT_BRANCH_IMAGE is automatically set to $CI_REGISTRY_IMAGE/$CI_DEFAULT_BRANCH:$CI_APPLICATION_TAG .

Using a custom SSL CA certificate authority

You can use the ADDITIONAL_CA_CERT_BUNDLE CI/CD variable to configure a custom SSL CA certificate authority, which is used to verify the peer when fetching Docker images from a registry which uses HTTPS. The ADDITIONAL_CA_CERT_BUNDLE value should contain the text representation of the X.509 PEM public-key certificate . For example, to configure this value in the .gitlab-ci.yml file, use the following:

container_scanning:
  variables:
    ADDITIONAL_CA_CERT_BUNDLE: |
        -----BEGIN CERTIFICATE-----
        MIIGqTCCBJGgAwIBAgIQI7AVxxVwg2kch4d56XNdDjANBgkqhkiG9w0BAQsFADCB
        jWgmPqF3vUbZE0EyScetPJquRFRKIesyJuBFMAs=
        -----END CERTIFICATE-----

The ADDITIONAL_CA_CERT_BUNDLE value can also be configured as a custom variable in the UI , either as a file , which requires the path to the certificate, or as a variable, which requires the text representation of the certificate.

Vulnerability allowlisting

To allowlist specific vulnerabilities, follow these steps:

1. Set GIT_STRATEGY: fetch in your .gitlab-ci.yml file by following the instructions in overriding the container scanning template .
2. Define the allowlisted vulnerabilities in a YAML file named vulnerability-allowlist.yml . This must use the format described in vulnerability-allowlist.yml data format .
3. Add the vulnerability-allowlist.yml file to the root folder of your project’s Git repository.

vulnerability-allowlist.yml data format

The vulnerability-allowlist.yml file is a YAML file that specifies a list of CVE IDs of vulnerabilities that are allowed to exist, because they’re false positives , or they’re not applicable .

If a matching entry is found in the vulnerability-allowlist.yml file, the following happens:

• The vulnerability is not included when the analyzer generates the gl-container-scanning-report.json file.
• The Security tab of the pipeline does not show the vulnerability. It is not included in the JSON file, which is the source of truth for the Security tab.

Example vulnerability-allowlist.yml file:

generalallowlist:
  CVE-2019-8696:
  CVE-2014-8166: cups
  CVE-2017-18248:
images:
  registry.gitlab.com/gitlab-org/security-products/dast/webgoat-8.0@sha256:
    CVE-2018-4180:
  your.private.registry:5000/centos:
    CVE-2015-1419: libxml2
    CVE-2015-1447:

This example excludes from gl-container-scanning-report.json :

1. All vulnerabilities with CVE IDs: CVE-2019-8696 , CVE-2014-8166 , CVE-2017-18248 .
2. All vulnerabilities found in the registry.gitlab.com/gitlab-org/security-products/dast/webgoat-8.0@sha256 container image with CVE ID CVE-2018-4180 .
3. All vulnerabilities found in your.private.registry:5000/centos container with CVE IDs CVE-2015-1419 , CVE-2015-1447 .

File format

generalallowlist block allows you to specify CVE IDs globally. All vulnerabilities with matching CVE IDs are excluded from the scan report.

images block allows you to specify CVE IDs for each container image independently. All vulnerabilities from the given image with matching CVE IDs are excluded from the scan report. The image name is retrieved from one of the environment variables used to specify the Docker image to be scanned, such as $CI_APPLICATION_REPOSITORY:$CI_APPLICATION_TAG or CS_IMAGE . The image provided in this block must match this value and must not include the tag value. For example, if you specify the image to be scanned using CS_IMAGE=alpine:3.7 , then you would use alpine in the images block, but you cannot use alpine:3.7 .

You can specify container image in multiple ways:

• as image name only (such as centos ).
• as full image name with registry hostname (such as your.private.registry:5000/centos ).
• as full image name with registry hostname and sha256 label (such as registry.gitlab.com/gitlab-org/security-products/dast/webgoat-8.0@sha256 ).

The string after CVE ID ( cups and libxml2 in the previous example) is an optional comment format. It has no impact on the handling of vulnerabilities. You can include comments to describe the vulnerability.

Container scanning job log format

You can verify the results of your scan and the correctness of your vulnerability-allowlist.yml file by looking at the logs that are produced by the container scanning analyzer in container_scanning job details.

The log contains a list of found vulnerabilities as a table, for example:

+------------+-------------------------+------------------------+-----------------------+------------------------------------------------------------------------+
|   STATUS   |      CVE SEVERITY       |      PACKAGE NAME      |    PACKAGE VERSION    |                            CVE DESCRIPTION                             |
+------------+-------------------------+------------------------+-----------------------+------------------------------------------------------------------------+
|  Approved  |   High CVE-2019-3462    |          apt           |         1.4.8         | Incorrect sanitation of the 302 redirect field in HTTP transport metho |
|            |                         |                        |                       | d of apt versions 1.4.8 and earlier can lead to content injection by a |
|            |                         |                        |                       |  MITM attacker, potentially leading to remote code execution on the ta |
|            |                         |                        |                       |                             rget machine.                              |
+------------+-------------------------+------------------------+-----------------------+------------------------------------------------------------------------+
| Unapproved |  Medium CVE-2020-27350  |          apt           |         1.4.8         | APT had several integer overflows and underflows while parsing .deb pa |
|            |                         |                        |                       | ckages, aka GHSL-2020-168 GHSL-2020-169, in files apt-pkg/contrib/extr |
|            |                         |                        |                       | acttar.cc, apt-pkg/deb/debfile.cc, and apt-pkg/contrib/arfile.cc. This |
|            |                         |                        |                       |  issue affects: apt 1.2.32ubuntu0 versions prior to 1.2.32ubuntu0.2; 1 |
|            |                         |                        |                       | .6.12ubuntu0 versions prior to 1.6.12ubuntu0.2; 2.0.2ubuntu0 versions  |
|            |                         |                        |                       | prior to 2.0.2ubuntu0.2; 2.1.10ubuntu0 versions prior to 2.1.10ubuntu0 |
|            |                         |                        |                       |                                  .1;                                   |
+------------+-------------------------+------------------------+-----------------------+------------------------------------------------------------------------+
| Unapproved |  Medium CVE-2020-3810   |          apt           |         1.4.8         | Missing input validation in the ar/tar implementations of APT before v |
|            |                         |                        |                       | ersion 2.1.2 could result in denial of service when processing special |
|            |                         |                        |                       |                         ly crafted deb files.                          |
+------------+-------------------------+------------------------+-----------------------+------------------------------------------------------------------------+

Vulnerabilities in the log are marked as Approved when the corresponding CVE ID is added to the vulnerability-allowlist.yml file.

registry.gitlab.com/security-products/container-scanning:6
registry.gitlab.com/security-products/container-scanning/grype:6
registry.gitlab.com/security-products/container-scanning/trivy:6