Implementing DevSecOps Security Scanning

When to Use

• Setting up automated security scanning in a new or existing CI/CD pipeline
• Shifting security left by catching vulnerabilities before code reaches production
• Meeting compliance requirements (SOC 2, PCI-DSS, ISO 27001) that mandate automated security testing
• Integrating SAST, DAST, and SCA together to achieve comprehensive application security coverage
• Establishing security gates that block deployments containing critical or high-severity vulnerabilities

Do not use as a replacement for manual penetration testing. Automated scanning catches common vulnerability patterns but cannot replace human-driven security assessments for business logic flaws and complex attack chains.

Prerequisites

• CI/CD platform: GitHub Actions, GitLab CI, Jenkins, or Azure DevOps
• Container runtime (Docker) for running scanning tools
• A staging environment URL for DAST scanning (DAST cannot test static code)
• Repository access with permissions to modify CI/CD workflow files
• Tool-specific requirements:
  • Semgrep: free for open-source rulesets (p/security-audit, p/owasp-top-ten)
  • Trivy: free, no account required
  • OWASP ZAP: free, Docker image available
  • Gitleaks: free, no account required

Workflow

Step 1: Add Secrets Detection with Gitleaks

Secrets detection runs first because leaked credentials are the highest-priority finding. Add to .github/workflows/security.yml:

name: DevSecOps Security Pipeline
on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]

jobs:
  secrets-scan:
    name: Secrets Detection (Gitleaks)
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Full history for scanning all commits

      - name: Run Gitleaks
        uses: gitleaks/gitleaks-action@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Configure .gitleaks.toml in the repository root for custom rules and allowlists:

[extend]
useDefault = true

[allowlist]
description = "Global allowlist"
paths = [
  '''\.gitleaks\.toml''',
  '''test/fixtures/.*''',
  '''docs/examples/.*'''
]

[[rules]]
id = "custom-internal-api-key"
description = "Internal API key pattern"
regex = '''INTERNAL_KEY_[A-Za-z0-9]{32}'''
tags = ["internal", "api-key"]

Step 2: Add SAST Scanning with Semgrep

Semgrep performs static code analysis to find security vulnerabilities, bugs, and code patterns:

  sast-scan:
    name: SAST (Semgrep)
    runs-on: ubuntu-latest
    container:
      image: semgrep/semgrep
    steps:
      - uses: actions/checkout@v4

      - name: Run Semgrep SAST scan
        run: |
          semgrep scan \
            --config p/security-audit \
            --config p/owasp-top-ten \
            --config p/secrets \
            --severity ERROR \
            --error \
            --json \
            --output semgrep-results.json \
            .

      - name: Upload SAST results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: semgrep-results
          path: semgrep-results.json

For custom rules, create .semgrep/custom-rules.yml:

rules:
  - id: no-exec-user-input
    patterns:
      - pattern: exec($INPUT)
      - pattern-not: exec("...")
    message: >
      User input passed to exec(). This is a command injection vulnerability.
    severity: ERROR
    languages: [python]
    metadata:
      cwe: "CWE-78: OS Command Injection"
      owasp: "A03:2021 - Injection"

  - id: no-raw-sql-queries
    patterns:
      - pattern: cursor.execute(f"...")
      - pattern: cursor.execute("..." + ...)
    message: >
      SQL query built with string concatenation or f-strings. Use parameterized queries.
    severity: ERROR
    languages: [python]
    metadata:
      cwe: "CWE-89: SQL Injection"
      owasp: "A03:2021 - Injection"

Step 3: Add SCA Scanning with Trivy

Trivy scans dependencies, container images, IaC files, and generates SBOM:

  sca-scan:
    name: SCA & Container Scan (Trivy)
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Run Trivy filesystem scan (dependencies)
        uses: aquasecurity/trivy-action@0.28.0
        with:
          scan-type: 'fs'
          scan-ref: '.'
          severity: 'CRITICAL,HIGH'
          exit-code: '1'
          format: 'json'
          output: 'trivy-fs-results.json'


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