Integrating SAST into GitHub Actions Pipeline

When to Use

• When development teams need automated code-level vulnerability detection on every pull request
• When security teams require consistent SAST enforcement across all repositories in an organization
• When migrating from manual or periodic security reviews to continuous security testing
• When compliance frameworks (SOC 2, PCI DSS, NIST SSDF) require evidence of automated code analysis
• When multiple languages coexist in a monorepo and need unified scanning under one workflow

Do not use for runtime vulnerability detection (use DAST instead), for scanning third-party dependencies (use SCA tools like Snyk), or for infrastructure-as-code scanning (use Checkov or tfsec).

Prerequisites

• GitHub repository with GitHub Actions enabled
• GitHub Advanced Security license (required for CodeQL on private repos; free for public repos)
• Semgrep account for managed rules and Semgrep App dashboard (free tier available)
• Repository code in a supported language: Python, JavaScript/TypeScript, Java, C/C++, C#, Go, Ruby, Swift, Kotlin

Workflow

Step 1: Configure CodeQL Analysis Workflow

Create a CodeQL workflow that runs on pull requests and on a weekly schedule to catch vulnerabilities in existing code.

# .github/workflows/codeql-analysis.yml
name: "CodeQL Analysis"

on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]
  schedule:
    - cron: '30 2 * * 1'  # Weekly Monday 2:30 AM

jobs:
  analyze:
    name: Analyze (${{ matrix.language }})
    runs-on: ubuntu-latest
    permissions:
      actions: read
      contents: read
      security-events: write

    strategy:
      fail-fast: false
      matrix:
        language: ['javascript', 'python']

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Initialize CodeQL
        uses: github/codeql-action/init@v3
        with:
          languages: ${{ matrix.language }}
          queries: security-extended,security-and-quality

      - name: Autobuild
        uses: github/codeql-action/autobuild@v3

      - name: Perform CodeQL Analysis
        uses: github/codeql-action/analyze@v3
        with:
          category: "/language:${{ matrix.language }}"

Step 2: Add Semgrep Scanning for Custom Rules

Semgrep complements CodeQL with faster scans and support for custom pattern-based rules. Configure it to upload SARIF results to the same GitHub Security tab.

# .github/workflows/semgrep.yml
name: "Semgrep SAST Scan"

on:
  pull_request:
    branches: [main, develop]
  push:
    branches: [main]

jobs:
  semgrep:
    name: Semgrep Scan
    runs-on: ubuntu-latest
    permissions:
      security-events: write
      contents: read

    container:
      image: semgrep/semgrep:latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Run Semgrep
        run: |
          semgrep ci \
            --config auto \
            --config p/owasp-top-ten \
            --config p/cwe-top-25 \
            --sarif --output semgrep-results.sarif \
            --severity ERROR \
            --error
        env:
          SEMGREP_APP_TOKEN: ${{ secrets.SEMGREP_APP_TOKEN }}

      - name: Upload SARIF
        if: always()
        uses: github/codeql-action/upload-sarif@v3
        with:
          sarif_file: semgrep-results.sarif
          category: semgrep

Step 3: Create Custom Semgrep Rules for Organization Patterns

Write organization-specific rules to catch patterns unique to your codebase, such as deprecated internal APIs or insecure configuration patterns.

# .semgrep/custom-rules.yml
rules:
  - id: hardcoded-database-url
    patterns:
      - pattern: |
          $DB_URL = "...$PROTO://...:...$PASS@..."
    message: |
      Hardcoded database connection string with credentials detected.
      Use environment variables or a secrets manager instead.
    languages: [python, javascript, typescript]
    severity: ERROR
    metadata:
      cwe: "CWE-798: Use of Hard-coded Credentials"
      owasp: "A07:2021 - Identification and Authentication Failures"

  - id: unsafe-deserialization
    patterns:
      - pattern-either:
          - pattern: pickle.loads(...)
          - pattern: yaml.load(..., Loader=yaml.Loader)
          - pattern: yaml.load(..., Loader=yaml.FullLoader)
    message: |
      Unsafe deserialization detected. Use safe alternatives to prevent

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