Secret Detection (FREE)

Moved from GitLab Ultimate to GitLab Free in 13.3.

A recurring problem when developing applications is that people may accidentally commit secrets to their remote Git repositories. Secrets include keys, passwords, API tokens, and other sensitive information. Anyone with access to the repository could use the secrets for malicious purposes. Secrets exposed in this way must be treated as compromised, and be replaced, which can be costly. It's important to prevent secrets from being committed to a Git repository.

Secret Detection uses the Gitleaks tool to scan the repository for secrets. All identified secrets are reported in the:

• Merge request widget
• Pipelines' Security tab
• Security Dashboard

WARNING: Secret Detection does not support scanning binary files.

Detected secrets

Secret Detection uses a default ruleset containing more than 90 secret detection patterns. You can also customize the secret detection patterns using custom rulesets. If you want to contribute rulesets for "well-identifiable" secrets, follow the steps detailed in the community contributions guidelines.

Requirements

To run Secret Detection jobs, by default, you need GitLab Runner with the docker or kubernetes executor. If you're using the shared runners on GitLab.com, this is enabled by default.

WARNING: Our Secret Detection jobs expect a Linux/amd64 container type. Windows containers are not supported.

WARNING: If you use your own runners, make sure the Docker version installed is not 19.03.0. See troubleshooting information for details.

Making Secret Detection available to all GitLab tiers

To make Secret Detection available to as many customers as possible, we have enabled it for all GitLab tiers. However not all features are available on every tier. See the breakdown below for more details.

Summary of features per tier

Different features are available in different GitLab tiers, as shown in the following table:

Configuration

• In GitLab 13.1, Secret Detection was split from the SAST configuration into its own CI/CD template. If you're using GitLab 13.0 or earlier and SAST is enabled, then Secret Detection is already enabled.
• In GitLab 14.0, Secret Detection jobs secret_detection_default_branch and secret_detection were consolidated into one job, secret_detection.

Secret Detection is performed by a specific analyzer during the secret-detection job. It runs regardless of your app's programming language.

The Secret Detection analyzer includes Gitleaks checks.

Note that the Secret Detection analyzer ignores Password-in-URL vulnerabilities if the password begins with a dollar sign ($), as this likely indicates the password is an environment variable. For example, https://username:$password@example.com/path/to/repo isn't detected, while https://username:password@example.com/path/to/repo is.

NOTE: You don't have to configure Secret Detection manually as shown in this section if you're using Auto Secret Detection, provided by Auto DevOps.

To enable Secret Detection for GitLab 13.1 and later, you must include the Secret-Detection.gitlab-ci.yml template that's provided as a part of your GitLab installation. For GitLab versions earlier than 11.9, you can copy and use the job as defined in that template.

Ensure your .gitlab-ci.yml file has a stage called test, and add the following to your .gitlab-ci.yml file:

include:
  - template: Security/Secret-Detection.gitlab-ci.yml

The included template creates Secret Detection jobs in your CI/CD pipeline and scans your project's source code for secrets.

The results are saved as a Secret Detection report artifact that you can later download and analyze. Due to implementation limitations, we always take the latest Secret Detection artifact available.

Supported distributions

The default scanner images are build off a base Alpine image for size and maintainability.

FIPS-enabled images

Introduced in GitLab 14.10.

GitLab offers Red Hat UBI versions of the images that are FIPS-enabled. To use the FIPS-enabled images, you can either:

• Set the SAST_IMAGE_SUFFIX to -fips.
• Add the -fips extension to the default image name.

For example:

variables:
  SECRET_DETECTION_IMAGE_SUFFIX: '-fips'

include:
  - template: Security/Secret-Detection.gitlab-ci.yml

Enable Secret Detection via an automatic merge request

• Introduced in GitLab 13.11, deployed behind a feature flag, enabled by default.
• Feature flag removed in GitLab 14.1.

NOTE: This method 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.

To enable Secret Detection in a project, you can create a merge request:

1. On the top bar, select Menu > Projects and find your project.
2. On the left sidebar, select Security & Compliance > Configuration.
3. In the Secret Detection row, select Configure with a merge request.
4. Review and merge the merge request to enable Secret Detection.

Pipelines now include a Secret Detection job.

Customizing settings

The Secret Detection scan settings can be changed through CI/CD variables by using the variables parameter in .gitlab-ci.yml.

WARNING: 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.

To override a job definition, (for example, change properties like variables or dependencies), declare a job with the same name as the secret detection job to override. Place this new job after the template inclusion and specify any additional keys under it.

WARNING: Beginning in GitLab 13.0, the use of only and except is no longer supported. When overriding the template, you must use rules instead.

GIT_DEPTH variable

The GIT_DEPTH CI/CD variable affects Secret Detection. The Secret Detection analyzer relies on generating patches between commits to scan content for secrets. If you override the default, ensure the value is greater than 1. If the number of commits in an MR is greater than the GIT_DEPTH value, Secret Detection will fail to detect secrets.

Custom settings example

In the following example, we include the Secret Detection template and at the same time we override the secret_detection job with the SECRET_DETECTION_HISTORIC_SCAN CI/CD variable to true:

include:
  - template: Security/Secret-Detection.gitlab-ci.yml

secret_detection:
  variables:
    SECRET_DETECTION_HISTORIC_SCAN: "true"

Because the template is evaluated before the pipeline configuration, the last mention of the variable takes precedence.

Available CI/CD variables

Secret Detection can be customized by defining available CI/CD variables:

In previous GitLab versions, the following variables were also available:

Custom rulesets (ULTIMATE)

• Introduced in GitLab 13.5.
• Added support for passthrough chains. Expanded to include additional passthrough types of file, git, and url in GitLab 14.6.
• Added support for overriding rules in GitLab 14.8.

You can customize the default secret detection rules provided with GitLab. Ruleset customization supports the following capabilities that can be used simultaneously:

• Disabling predefined rules.
• Overriding predefined rules.
• Modifying the default behavior of the Secret Detection analyzer by synthesizing and passing a custom configuration.

Customization allows replacing the default secret detection rules with rules that you define.

To create a custom ruleset:

1. Create a .gitlab directory at the root of your project, if one doesn't already exist.
2. Create a custom ruleset file named secret-detection-ruleset.toml in the .gitlab directory.

Disable predefined analyzer rules

To disable analyzer rules:

1. Set the disabled flag to true in the context of a ruleset section.

2. In one or more ruleset.identifier subsections, list the rules that you want disabled. Every ruleset.identifier section has:

   • a type field, to name the predefined rule identifier.
   • a value field, to name the rule to be disabled.

Example: Disable predefined rules of Secret Detection analyzer

In the following example, the disabled rules is assigned to secrets by matching the type and value of identifiers:

[secrets]
  [[secrets.ruleset]]
    disable = true
    [secrets.ruleset.identifier]
      type = "gitleaks_rule_id"
      value = "RSA private key"

Override predefined analyzer rules

To override rules:

1. In one or more ruleset.identifier subsections, list the rules that you want to override. Every ruleset.identifier section has:

   • a type field, to name the predefined rule identifier that the Secret Detection analyzer uses.
   • a value field, to name the rule to be overridden.

2. In the ruleset.override context of a ruleset section, provide the keys to override. Any combination of keys can be overridden. Valid keys are:

   • description
   • message
   • name
   • severity (valid options are: Critical, High, Medium, Low, Unknown, Info)

Example: Override predefined rules of Secret Detection analyzer

In the following example, rules are matched by the type and value of identifiers and then overridden:

[secrets]
  [[secrets.ruleset]]
    [secrets.ruleset.identifier]
      type = "gitleaks_rule_id"
      value = "RSA private key"
    [secrets.ruleset.override]
      description = "OVERRIDDEN description"
      message = "OVERRIDDEN message"
      name = "OVERRIDDEN name"
      severity = "Info"

Synthesize a custom configuration

To create a custom configuration, you can use passthrough chains.

1. In the secret-detection-ruleset.toml file, do one of the following:

   • Define a custom ruleset:

     [secrets]
       description = 'secrets custom rules configuration'
     
       [[secrets.passthrough]]
         type  = "raw"
         target = "gitleaks.toml"
         value = """\
     title = "gitleaks config"
     # add regexes to the regex table
     [[rules]]
     description = "Test for Raw Custom Rulesets"
     regex = '''Custom Raw Ruleset T[est]{3}'''
     """

   • Provide the name of the file containing a custom ruleset:

     [secrets]
       description = 'secrets custom rules configuration'
     
       [[secrets.passthrough]]
         type  = "file"
         target = "gitleaks.toml"
         value = "config/gitleaks.toml"

Passthroughs can also be chained to build more complex configurations. For more details, see SAST Customize ruleset section.

Logging level

To control the verbosity of logs set the SECURE_LOG_LEVEL CI/CD variable. Messages of this logging level or higher are output. Introduced in GitLab 13.1.

From highest to lowest severity, the logging levels are:

• fatal
• error
• warn
• info (default)
• debug

Post-processing and revocation

Upon detection of a secret, GitLab SaaS supports post-processing hooks. For more information, see Post-processing and revocation.

Full History Secret Detection

GitLab 12.11 introduced support for scanning the full history of a repository. This new functionality is particularly useful when you are enabling Secret Detection in a repository for the first time and you want to perform a full secret detection scan. Running a secret detection scan on the full history can take a long time, especially for larger repositories with lengthy Git histories. We recommend not setting this CI/CD variable as part of your normal job definition.

A new configuration variable (SECRET_DETECTION_HISTORIC_SCAN) can be set to change the behavior of the GitLab Secret Detection scan to run on the entire Git history of a repository.

Running Secret Detection in an offline environment

For self-managed GitLab instances in an environment with limited, restricted, or intermittent access to external resources through the internet, some adjustments are required for the Secret Detection job to run successfully. For more information, see Offline environments.

Requirements for offline Secret Detection

To use Secret Detection in an offline environment, you need:

• GitLab Runner with the docker or kubernetes executor.
• A Docker Container Registry with locally available copy of Secret Detection analyzer images.
• Configure certificate checking of packages (optional).

GitLab Runner has a default pull policy of always, meaning the runner tries to pull Docker images from the GitLab container registry even if a local copy is available. The GitLab Runner pull_policy can be set to if-not-present in an offline environment if you prefer using only locally available Docker images. However, we recommend keeping the pull policy setting to always if not in an offline environment, as this enables the use of updated scanners in your CI/CD pipelines.

Make GitLab Secret Detection analyzer image available inside your Docker registry

Import the following default Secret Detection analyzer images from registry.gitlab.com into your local Docker container registry:

registry.gitlab.com/security-products/secret-detection:3

The process for importing Docker images into a local offline Docker registry depends on your network security policy. Please consult your IT staff to find an accepted and approved process by which external resources can be imported or temporarily accessed. These scanners are periodically updated with new definitions, and you may be able to make occasional updates on your own.

For details on saving and transporting Docker images as a file, see Docker's documentation on docker save, docker load, docker export, and docker import.

Set Secret Detection CI/CD variables to use the local Secret Detection analyzer container image

Add the following configuration to your .gitlab-ci.yml file. You must replace SECURE_ANALYZERS_PREFIX to refer to your local Docker container registry:

include:
  - template: Security/Secret-Detection.gitlab-ci.yml

variables:
  SECURE_ANALYZERS_PREFIX: "localhost:5000/analyzers"

The Secret Detection job should now use the local copy of the Secret Detection analyzer Docker image to scan your code and generate security reports without requiring internet access.

If support for Custom Certificate Authorities are needed

Support for custom certificate authorities was introduced in the following versions.

To trust a custom Certificate Authority, set the ADDITIONAL_CA_CERT_BUNDLE variable to the bundle of CA certs that you want to trust in the SAST environment. 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:

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.

Troubleshooting

Getting warning message gl-secret-detection-report.json: no matching files

For information on this, see the general Application Security troubleshooting section.

Error: Couldn't run the gitleaks command: exit status 2

If a pipeline is triggered from a merge request containing 60 commits while the GIT_DEPTH variable's value is less than that, the Secret Detection job fails as the clone is not deep enough to contain all of the relevant commits. For information on the current default value, see the pipeline configuration documentation.

To confirm this as the cause of the error, set the logging level to debug, then rerun the pipeline. The logs should look similar to the following example. The text "object not found" is a symptom of this error.

ERRO[2020-11-18T18:05:52Z] object not found
[ERRO] [secrets] [2020-11-18T18:05:52Z] ▶ Couldn't run the gitleaks command: exit status 2
[ERRO] [secrets] [2020-11-18T18:05:52Z] ▶ Gitleaks analysis failed: exit status 2

To resolve the issue, set the GIT_DEPTH CI/CD variable to a higher value. To apply this only to the Secret Detection job, the following can be added to your .gitlab-ci.yml file:

secret_detection:
  variables:
    GIT_DEPTH: 100

secret-detection job fails with ERR fatal: ambiguous argument message

Your secret-detection job can fail with ERR fatal: ambiguous argument error if your repository's default branch is unrelated to the branch the job was triggered for. See issue !352014 for more details.

To resolve the issue, make sure to correctly set your default branch on your repository. You should set it to a branch that has related history with the branch you run the secret-detection job on.