Secret Detection (FREE)

• 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.
• Moved from GitLab Ultimate to GitLab Free in 13.3.
• In GitLab 14.0, Secret Detection jobs secret_detection_default_branch and secret_detection were consolidated into one job, secret_detection.

People may accidentally commit secrets to 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. Exposed secrets are compromised and must be replaced, which can be costly.

To help prevent secrets from being committed to a Git repository, you can use Secret Detection to scan your repository for secrets. Scanning is language and framework agnostic, but does not support scanning binary files.

Secret Detection uses a specific analyzer containing the Gitleaks tool to scan the repository for secrets, in a secret-detection job. 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.

GitLab SaaS supports post-processing hooks, so you can take action when a secret is found. For more information, see Post-processing and revocation.

All identified secrets are reported in the:

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

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.

Features per tier

Different features are available in different GitLab tiers.

Enable Secret Detection

Prerequisites:

• GitLab Runner with the docker or kubernetes executor. If you're using the shared runners on GitLab.com, this is enabled by default.
• If you use your own runners, make sure the Docker version installed is not 19.03.0. See troubleshooting information for details.
• Linux/amd64 container type. Windows containers are not supported.
• GitLab CI/CD configuration (.gitlab-ci.yml) must include the test stage.

To enable Secret Detection, either:

• Enable Auto DevOps, which includes Auto Secret Detection.

• Enable Secret Detection by including the template.

• Enable Secret Detection using a merge request.

Enable Secret Detection by including the template

We recommend this method if you have an existing GitLab CI/CD configuration file.

Add the following extract to your .gitlab-ci.yml file:

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

Pipelines now include a Secret Detection job, and the results are included in the merge request widget.

Enable Secret Detection using a 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 using a merge request:

1. On the top bar, select Main 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.

Pipelines now include a Secret Detection job, and the results are included in the merge request widget.

Configure scan settings

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

WARNING: All configuration 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.

In the following example extract of a .gitlab-ci.yml file:

• The Secret Detection template is included.
• In the secret_detection job, the CI/CD variable SECRET_DETECTION_HISTORIC_SCAN is set to true. Because the template is evaluated before the pipeline configuration, the last mention of the variable takes precedence.

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

secret_detection:
  variables:
    SECRET_DETECTION_HISTORIC_SCAN: "true"

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:

Use FIPS-enabled images

Introduced in GitLab 14.10.

The default scanner images are built off a base Alpine image for size and maintainability. GitLab offers Red Hat UBI versions of the images that are FIPS-enabled.

To use the FIPS-enabled images, either:

• Set the SECRET_DETECTION_IMAGE_SUFFIX CI/CD variable 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

Full history Secret Detection

By default, Secret Detection scans only the current state of the Git repository. Any secrets contained in the repository's history are not detected. To address this, Secret Detection can scan the Git repository's full history.

We recommend you do a full history scan only once, after enabling Secret Detection. A full history can take a long time, especially for larger repositories with lengthy Git histories. After completing an initial full history scan, use only standard Secret Detection as part of your pipeline.

Enable full history Secret Detection

To enable full history Secret Detection, set the variable SECRET_DETECTION_HISTORIC_SCAN to true in your .gitlab-ci.yml file.

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.

The following customization options can be used separately, or in combination:

• Disable predefined rules.
• Override predefined rules.
• Synthesize a custom configuration.

Disable predefined analyzer rules

If there are specific Secret Detection rules that you don't want active, you can disable them.

To disable analyzer rules:

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, if one doesn't already exist.
3. Set the disabled flag to true in the context of a ruleset section.
4. In one or more ruleset.identifier subsections, list the rules to disable. Every ruleset.identifier section has:
   • A type field for the predefined rule identifier.
   • A value field for the rule name.

In the following example secret-detection-ruleset.toml file, the disabled rules are 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

If there are specific Secret Detection rules you want to customize, you can override them. For example, you might increase the severity of specific secrets.

To override rules:

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, if one doesn't already exist.
3. In one or more ruleset.identifier subsections, list the rules to override. Every ruleset.identifier section has:
   • A type field for the predefined rule identifier.
   • A value field for the rule name.
4. 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)

In the following example secret-detection-ruleset.toml file, 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. Passthroughs can also be chained to build more complex configurations. For more details, see SAST Customize ruleset.

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

• Define a custom ruleset, for example:

  [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, for example:

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

Running Secret Detection in an offline environment (PREMIUM SELF)

For self-managed GitLab instances in an environment with limited, restricted, or intermittent access to external resources through the internet, some configuration changes are required for the Secret Detection job to run successfully. The instructions in this section must be completed together with the instructions detailed in offline environments.

Configure GitLab Runner

By default, a runner tries to pull Docker images from the GitLab container registry even if a local copy is available. We recommend using this default setting, to ensure Docker images remain current. However, if no network connectivity is available, you must change the default GitLab Runner pull_policy variable.

Configure the GitLab Runner CI/CD variable pull_policy to if-not-present.

Use local Secret Detection analyzer image

Use a local Secret Detection analyzer image if you want to obtain the image from a local Docker registry instead of the GitLab container registry.

Prerequisites:

• Importing Docker images into a local offline Docker registry depends on your network security policy. Consult your IT staff to find an accepted and approved process to import or temporarily access external resources.

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

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

   The Secret Detection analyzer's image is periodically updated so you may need to periodically update the local copy.

2. Set the CI/CD variable SECURE_ANALYZERS_PREFIX to the 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, without requiring internet access.

Configure a custom Certificate Authority

To trust a custom Certificate Authority, set the ADDITIONAL_CA_CERT_BUNDLE variable to the bundle of CA certificates that you trust. Do this either in the .gitlab-ci.yml file, in a file variable, or as a CI/CD variable.

• In the .gitlab-ci.yml file, the ADDITIONAL_CA_CERT_BUNDLE value must contain the text representation of the X.509 PEM public-key certificate.

  For example:

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

• If using a file variable, set the value of ADDITIONAL_CA_CERT_BUNDLE to the path to the certificate.

• If using a variable, set the value of ADDITIONAL_CA_CERT_BUNDLE to the text representation of the certificate.

Troubleshooting

Set the logging level

Introduced in GitLab 13.1.

Set the logging level to debug when you need diagnostic information in a Secret Detection job log.

WARNING: Debug logging can be a serious security risk. The output may contain the content of environment variables and other secrets available to the job. The output is uploaded to the GitLab server and visible in job logs.

1. In the .gitlab-ci.yml file, set the SECURE_LOG_LEVEL CI/CD variable to debug.
2. Run the Secret Detection job.
3. Analyze the content of the Secret Detection job.
4. In the .gitlab-ci.yml file, set the SECURE_LOG_LEVEL CI/CD variable to info (default).

Warning: 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

The Secret Detection analyzer relies on generating patches between commits to scan content for secrets. If the number of commits in a merge request is greater than the value of the GIT_DEPTH CI/CD variable, Secret Detection fails to detect secrets.

For example, if a pipeline is triggered from a merge request containing 60 commits and the GIT_DEPTH variable's value is less than 60, the Secret Detection job fails as the clone is not deep enough to contain all of the relevant commits. To veridy the current value, see pipeline configuration.

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

Error: ERR fatal: ambiguous argument

Secret Detection can fail with the message 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.