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Royser Alonsso Villanueva Mamani
Royser Alonsso Villanueva Mamani

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Applying Any SAST Tools for Infrastructure-as-Code (IaC) Applications

#tooling #devops #infrastructureascode

When managing Infrastructure as Code (IaC), security becomes just as essential as automation and scalability. Misconfigurations in cloud resources—such as overly permissive IAM roles, insecure storage buckets, or weak network rules—can lead to serious vulnerabilities. To prevent this, Software Composition Analysis (SCA) and Security Static Application Security Testing (SAST) tools help detect issues early in the development lifecycle.

This article explains how to apply SAST tools to IaC projects, focusing on Terraform, Pulumi, OpenTofu, and similar technologies—without relying on TFSEC—and based on the OWASP Source Code Analysis Tools recommendations.

Why Use SAST Tools for IaC?

Traditional SAST tools focus on application code, but modern cloud-native systems require scanning configuration code as well. IaC brings many benefits, but also risks:

  • Human errors become reproducible vulnerabilities
  • Cloud misconfigurations scale instantly across environments
  • Secrets may accidentally be committed to repositories
  • Non-secure defaults lead to insecure architectures

SAST tools analyze IaC definitions before deployment, ensuring compliance with security policies.

OWASP Perspective on Source Code Analysis Tools

OWASP categorizes source code analysis tools into:

  • Static Application Security Testing (SAST)
  • Software Composition Analysis (SCA)
  • Hybrid analysis tools

These tools help identify vulnerabilities early, reduce attack surface, and ensure best practices. For IaC, similar concepts apply—but the focus shifts to configuration-level risks.

OWASP’s guidance (see OWASP Source Code Analysis Tools list) encourages:

  • automated scanning,
  • integrating tools into CI/CD,
  • scanning all configuration files,
  • and preventing insecure deployments.

Supported IaC Types

SAST tools can analyze multiple IaC formats:

  • Terraform (.tf, .tfvars)
  • Pulumi (TypeScript, Python, Go, C#, YAML)
  • OpenTofu (same format as Terraform)
  • CloudFormation (YAML/JSON)
  • Kubernetes YAML
  • Ansible, Helm, and others (varies by tool)

Popular SAST Tools for IaC (Except TFSEC)

Here are widely adopted tools you can apply immediately:

Checkov (Bridgecrew / Palo Alto Networks)

  • Supports Terraform, OpenTofu, Pulumi, CloudFormation, Kubernetes
  • Highly customizable policies (YAML or Python)
  • Pre-commit hook support

KICS (Keep Infrastructure as Code Secure)

  • Open-source by Checkmarx
  • Scans Terraform, CloudFormation, Kubernetes, Ansible
  • Includes hundreds of rules mapped to standards like CIS

Terrascan

  • Open-source by Tenable
  • Supports Terraform, Kubernetes, Helm, kustomize
  • Can run as CLI or inside CI/CD

Semgrep

  • Can create rules for IaC (YAML-based rule sets)
  • Works for Kubernetes, Docker, Terraform (via community rules)
  • Very fast and lightweight

Checkmarx One, Snyk IaC, Aqua Trivy, Prowler

(Commercial and open-source options)

Applying SAST to Terraform, Pulumi, and OpenTofu

📌 Example Workflow (Terraform/OpenTofu)

checkov -d .
kics scan -p .
terrascan scan -d .
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📌 Example Workflow (Pulumi – TypeScript)

semgrep scan --config="p/terraform" .
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Pulumi generates cloud resources using programming languages; some SAST tools scan the final state files, while others scan Pulumi code directly.

Integrating SAST into CI/CD Pipelines

Example (GitHub Actions)

name: IaC Security Scan
on: [push, pull_request]

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Run Checkov
        uses: bridgecrewio/checkov-action@v12
        with:
          directory: .

      - name: Run KICS
        uses: Checkmarx/kics-action@v1
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Example (GitLab CI)

iac_scan:
  script:
    - checkov -d .
    - terrascan scan -d .
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Example (Azure DevOps)

steps:
  - script: checkov -d .
    displayName: "Run Checkov"
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Best Practices When Using IaC SAST Tools

  1. Shift security left—run scans at commit time.
  2. Automate everything—never rely on manual review alone.
  3. Create custom policies relevant to your organization.
  4. Fail builds on critical violations.
  5. Version-control your security rules.
  6. Scan all environments, including feature branches.
  7. Avoid exceptions unless necessary.

Conclusion

Applying SAST tools to Infrastructure-as-Code is essential for securing cloud-native environments. By adopting tools such as Checkov, KICS, Terrascan, and Semgrep—and integrating them into CI/CD pipelines—you ensure that every cloud resource is secure before deployment.

OWASP’s recommendations align perfectly with this proactive approach: automate scans, integrate early, and enforce security consistently.

IaC security is no longer optional—it's part of modern DevSecOps.

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