cfn-nag

At a glance

• Editor score
  7.7 / 10
• Pricing
  Free plan
• Best for
  Free CloudFormation rule scanning
• Free plan
  Yes
• Paid from
  None
• Custom policies
  Yes
• Facts checked
  20 Sep 2026

• Where it wins

  • Covers IAM, security groups, logging, encryption, and password literals
  • Supports custom rules, rule profiles, deny lists, and suppressions
  • Runs locally, in Docker, GitHub Actions, and AWS CodePipeline

• Where it doesn't

  • Analyzes CloudFormation only, not Terraform or Kubernetes
  • Integration coverage centers on GitHub Actions and AWS services
  • Requires command-line workflows rather than a broader visual interface

Our verdict on cfn-nag

cfn-nag is an open-source Ruby command-line tool for auditing AWS CloudFormation templates against patterns associated with insecure infrastructure. It suits developers and platform teams that want focused rule scanning for JSON, YAML, and template files across macOS, Linux, or self-hosted environments. Findings cover overly permissive IAM and security-group rules, missing access logging or encryption, and password literals. Results can be returned as text or JSON, making the tool suitable for local checks and automated pipelines.

Its main strength is configurable policy depth within a narrow framework. Teams can use rule profiles and global deny lists, suppress findings for individual resources, provide parameter values, and create custom rules or custom rule repositories. That makes cfn-nag more adaptable than a fixed checklist while keeping its focus on CloudFormation. The Docker-based GitHub Action supports repository automation, and integrations also include AWS CodePipeline and the AWS Serverless Application Repository.

The trade-off is breadth. cfn-nag does not analyze Terraform or Kubernetes, so organizations managing multiple infrastructure-as-code frameworks will need additional tooling for those files. Its listed workflow is centered on a Ruby CLI, local or self-hosted execution, Docker, and selected AWS or GitHub integrations. Choose cfn-nag when free, open-source CloudFormation scanning and customizable rules are the priority. Consider an alternative when the requirement is multi-framework analysis, a wider integration ecosystem, or a workflow built around interfaces beyond command-line and pipeline execution.

cfn-nag pricing

cfn-nag fact sheet

cfn-nag integrations

cfn-nag lists 3 integrations on its own site.

• GitHub Actions
• AWS CodePipeline
• AWS Serverless Application Repository

Alternatives to cfn-nag

• KICSA broad, free IaC scanner for security, compliance, secrets, and misconfigurations.9.4
• CheckovA free, multi-framework IaC scanner with custom policies, graph analysis, and CI/CD support.9.3
• Snyk IaCA broad IaC security layer for teams that need scanning, governance, and drift management.9.1

See all cfn-nag alternatives →

Also listed in

• Infrastructure Testing Tools
• IaC Security Scanners

Featured on iTechGuides

cfn-nag is listed in our Infrastructure as Code Security Software directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update