cfn-nag review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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 pros and cons

• 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

cfn-nag fact sheet, pricing and score →

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Last updated 7 Oct 2026 · How we research and update