Terraform security scanning tools - Commands & Configuration

Introduction

Terraform security scanning tools help find security problems in your infrastructure code before you use it. They check your Terraform files to make sure you don't accidentally create unsafe setups.

Before applying Terraform code to production to catch security risks early.

When reviewing Terraform code written by your team to ensure it follows security rules.

To automate security checks in your code pipeline so unsafe changes are blocked.

When you want to learn about common security mistakes in Terraform configurations.

To verify compliance with company or industry security standards in infrastructure.

Config File - main.tf

main.tf

terraform {
  required_version = ">= 1.0"
}

provider "aws" {
  region = "us-east-1"
}

resource "aws_s3_bucket" "example" {
  bucket = "example-secure-bucket"
  acl    = "private"

  versioning {
    enabled = true
  }

  server_side_encryption_configuration {
    rule {
      apply_server_side_encryption_by_default {
        sse_algorithm = "AES256"
      }
    }
  }
}

This Terraform file creates an AWS S3 bucket with security best practices:

• acl = "private" keeps the bucket private.
• versioning enabled protects against accidental deletes.
• server_side_encryption_configuration encrypts data at rest.

Security scanning tools will check for these settings to ensure the bucket is secure.

Commands

This command initializes the Terraform working directory. It downloads necessary provider plugins and prepares the environment for further commands.

Terminal

terraform init

Expected Output

Initializing the backend...



Initializing provider plugins...

- Finding latest version of hashicorp/aws...

- Installing hashicorp/aws v4.0.0...

- Installed hashicorp/aws v4.0.0 (signed by HashiCorp)



Terraform has been successfully initialized!



You may now begin working with Terraform. Try running "terraform plan" to see any changes that are required for your infrastructure.

This command checks your Terraform files for syntax errors and basic correctness before applying them.

Terminal

terraform validate

Expected Output

Success! The configuration is valid.

This command initializes TFLint, a Terraform linter that can detect security and style issues in your Terraform code.

Terminal

tflint --init

Expected Output

INFO: Initializing TFLint...

INFO: Plugin aws installed

INFO: Initialization completed

This command runs TFLint to scan your Terraform files for security issues and best practice violations.

Terminal

tflint

Expected Output

No issues found!

This command runs Checkov, a security scanner for Terraform, to detect security misconfigurations in your Terraform directory.

Terminal

checkov -d .

Expected Output

Passed checks: 10, Failed checks: 0, Skipped checks: 0



Checkov scan completed successfully.

Key Concept

If you remember nothing else from this pattern, remember: always scan your Terraform code with security tools before applying it to catch risks early.

Common Mistakes

Running terraform apply without running security scans first

This can deploy insecure infrastructure that may expose data or cause outages.

Always run security scanning tools like TFLint or Checkov before applying Terraform changes.

Ignoring warnings or errors from security scanning tools

Warnings often indicate real security risks that should be fixed to protect your infrastructure.

Review and fix all security warnings before deploying your Terraform code.

Not initializing security tools before scanning

Tools like TFLint require initialization to download rules and plugins; skipping this causes scan failures.

Run initialization commands like 'tflint --init' before scanning.

Summary

Initialize Terraform and providers with 'terraform init' to prepare your environment.

Validate Terraform files with 'terraform validate' to catch syntax errors early.

Use TFLint and Checkov commands to scan Terraform code for security issues.

Fix any security warnings before applying infrastructure changes.