Semgrep step configuration

You can scan your code repositories using Semgrep and ingest the results into STO.

For a quick introduction, go to the SAST code scans using Semgrep tutorial.

Important notes for running Semgrep scans in STO

• This integration uses the Semgrep Engine, which is open-source and licensed under LGPL 2.1.

  To run scans using a licensed version of Semgrep Code, add your Semgrep token in the Access token field.

• STO Semgrep steps include the following rulesets by default:

  • auto
  • bandit
  • brakeman
  • eslint
  • findsecbugs
  • flawfinder
  • gosec
  • phps-security-audit
  • security-code-scan

  Some rulesets include Pro rules that are available only with a paid version of Semgrep. For more information, go to the Semgrep Registry.

• If you want to add trusted certificates to your scan images at runtime, you need to run the scan step with root access.

  You can set up your STO scan images and pipelines to run scans as non-root and establish trust for your proxies using custom certificates. For more information, go to Configure STO to Download Images from a Private Registry.

• The following topics contain useful information for setting up scanner integrations in STO:

  • What's supported in STO
  • Security Testing Orchestration FAQs
  • Optimize STO pipelines

Set-up workflows

Add a built-in SAST scanner (easiest)

To scan a code repository, you need Harness Code Repository or a Harness connector to your Git service.

Add the built-in SAST scanner

Do the following:

1. Add a Build or Security stage to your pipeline.

2. Configure the stage to point to the codebase you want to scan.

3. Go to the Execution tab, click Add step, and select the SAST built-in scanner.

   

4. Select Semgrep and then Add scanner.

5. Save your pipeline and then click Run.

   The pipeline scans your code repository and then shows the results in Security Tests.

Orchestration scans

To scan a code repository, you need Harness Code Repository or a Harness connector to your Git service.

Add the Semgrep scanner

Do the following:

1. Add a Build or Security stage to your pipeline.
2. Configure the stage to point to the codebase you want to scan.
3. Add a Semgrep step to the stage.

Set up the Semgrep scanner

Required settings

1. Scan mode = Orchestration
2. Target and Variant Detection = Auto

Optional settings

• Fail on Severity — Stop the pipeline if the scan detects any issues at a specified severity or higher
• Log Level — Useful for debugging

Scan the repository

Save your pipeline and then select Run.

The pipeline scans your code repository and then shows the results in Security Tests.

Ingestion scans

Add a shared path for your scan results

1. Add a Build or Security stage to your pipeline.
2. In the stage Overview, add a shared path such as /shared/scan_results.

Copy scan results to the shared path

There are two primary workflows to do this:

• Add a Run step that runs a Semgrep scan from the command line and then copies the results to the shared path.
• Copy results from a Semgrep scan that ran outside the pipeline.

For more information and examples, go to Ingestion scans.

Set up the Semgrep scanner

Add a Semgrep step to the stage and set it up as follows.

Required settings

1. Scan mode = Ingestion
2. Target name — Usually the repo name
3. Target variant — Usually the scanned branch. You can also use a runtime input and specify the branch at runtime.
4. Ingestion file — For example, /shared/scan_results/semgrep-scan.json

Optional settings

• Fail on Severity — Stop the pipeline if the scan detects any issues at a specified severity or higher
• Log Level — Useful for debugging

Scan the repository

Save your pipeline and then select Run.

The pipeline scans your code repository and then shows the results in Security Tests.

Semgrep step configuration

The recommended workflow is to add a Semgrep step to a Security Tests or CI Build stage and then configure it as described below.

Scan

Scan Mode

• Orchestration Configure the step to run a scan and then ingest, normalize, and deduplicate the results.

• Ingestion Configure the step to read scan results from a data file and then ingest, normalize, and deduplicate the data.

Scan Configuration

You can use this setting to select the set of Semgrep rulesets to include in your scan:

• Default Include the following rulesets:
  • bandit
  • brakeman
  • eslint
  • findsecbugs
  • flawfinder
  • gosec
  • phps-security-audit
  • security-code-scan
• No default CLI flags Run the semgrep scanner with no additional CLI flags. This setting is useful if you want to specify a custom set of rulesets in Additional CLI flags.
• p/default Run the scan with the default ruleset configured for the Semgrep scanner.
• Auto only Run the scan with the recommended rulesets specific to your project.
• Auto and Ported security tools Include the following rulesets:
  • auto
  • brakeman
  • eslint
  • findsecbugs
  • flawfinder
  • gitleaks
  • gosec
  • phps-security-audit
  • security-code-scan
• Auto and Ported security tools except p/gitleaks

Target

Type

• Repository Scan a codebase repo.

  In most cases, you specify the codebase using a code repo connector that connects to the Git account or repository where your code is stored. For information, go to Configure codebase.

Target and variant detection

When Auto is enabled for code repositories, the step detects these values using git:

• To detect the target, the step runs git config --get remote.origin.url.
• To detect the variant, the step runs git rev-parse --abbrev-ref HEAD. The default assumption is that the HEAD branch is the one you want to scan.

Note the following:

• Auto is not available when the Scan Mode is Ingestion.
• Auto is the default selection for new pipelines. Manual is the default for old pipelines, but you might find that neither radio button is selected in the UI.

Name

The identifier for the target, such as codebaseAlpha or jsmith/myalphaservice. Descriptive target names make it much easier to navigate your scan data in the STO UI.

It is good practice to specify a baseline for every target.

Variant

The identifier for the specific variant to scan. This is usually the branch name, image tag, or product version. Harness maintains a historical trend for each variant.

Workspace

The workspace path on the pod running the scan step. The workspace path is /harness by default.

You can override this if you want to scan only a subset of the workspace. For example, suppose the pipeline publishes artifacts to a subfolder /tmp/artifacts and you want to scan these artifacts only. In this case, you can specify the workspace path as /harness/tmp/artifacts.

Ingestion File

The path to your scan results when running an Ingestion scan, for example /shared/scan_results/myscan.latest.sarif.

• The data file must be in a supported format for the scanner.

• The data file must be accessible to the scan step. It's good practice to save your results files to a shared path in your stage. In the visual editor, go to the stage where you're running the scan. Then go to Overview > Shared Paths. You can also add the path to the YAML stage definition like this:

      - stage:
        spec:
          sharedPaths:
            - /shared/scan_results

Access Token

The access token to log in to the scanner. This is usually a password or an API key.

You should create a Harness text secret with your encrypted token and reference the secret using the format <+secrets.getValue("my-access-token")>. For more information, go to Add and Reference Text Secrets.

Log Level

The minimum severity of the messages you want to include in your scan logs. You can specify one of the following:

• DEBUG
• INFO
• WARNING
• ERROR

Additional CLI flags

Use this field to run the semgrep scanner with flags such as:

--severity=ERROR --use-git-ignore

With these flags, semgrep considers only ERROR severity rules and ignores files included in .gitignore.

caution

Passing additional CLI flags is an advanced feature. Harness recommends the following best practices:

• Test your flags and arguments thoroughly before you use them in your Harness pipelines. Some flags might not work in the context of STO.

• Don't add flags that are already used in the default configuration of the scan step.

  To check the default configuration, go to a pipeline execution where the scan step ran with no additional flags. Check the log output for the scan step. You should see a line like this:

  Command [ scancmd -f json -o /tmp/output.json ]

  In this case, don't add -f or -o to Additional CLI flags.

Fail on Severity

Every STO scan step has a Fail on Severity setting. If the scan finds any vulnerability with the specified severity level or higher, the pipeline fails automatically. You can specify one of the following:

• CRITICAL
• HIGH
• MEDIUM
• LOW
• INFO
• NONE — Do not fail on severity

The YAML definition looks like this: fail_on_severity : critical # | high | medium | low | info | none

Settings

You can use this field to specify environment variables for your scanner.

Additional Configuration

In the Additional Configuration settings, you can use the following options:

• Privileged
• Image Pull Policy
• Run as User
• Set Container Resources
• Timeout

Advanced settings

In the Advanced settings, you can use the following options:

• Conditional Execution
• Failure Strategy
• Looping Strategy
• Policy Enforcement

YAML pipeline example

The following pipeline example illustrates an orchestration workflow. It consists of a Semgrep step that scans a code repository and then ingests, normalizes, and deduplicates the results.

pipeline:
  name: semgrep-orch-test
  identifier: semgreporchtest
  projectIdentifier: default
  orgIdentifier: default
  tags: {}
  properties:
    ci:
      codebase:
        connectorRef: YOUR_GIT_CONNECTOR_ID
        repoName: YOUR_GIT_REPO_NAME
        build: <+input>
  stages:
    - stage:
        name: semgrep-orch
        identifier: semgreporch
        description: ""
        type: SecurityTests
        spec:
          cloneCodebase: true
          platform:
            os: Linux
            arch: Amd64
          runtime:
            type: Cloud
            spec: {}
          execution:
            steps:
              - step:
                  type: Semgrep
                  name: Semgrep_1
                  identifier: Semgrep_1
                  spec:
                    mode: orchestration
                    config: default
                    target:
                      type: repository
                      detection: auto
                    advanced:
                      log:
                        level: info