Static Analysis Tools for Terraform

Static Analysis Tools for Terraform

Static analysis tools examine Terraform code without executing it, identifying security issues through pattern matching and policy evaluation. These tools integrate early in the development process, providing immediate feedback to developers writing infrastructure code. Modern static analysis goes beyond simple pattern matching to understand Terraform's resource relationships and implicit configurations.

Tfsec stands out as a comprehensive open-source security scanner specifically designed for Terraform. It includes hundreds of built-in checks covering AWS, Azure, and Google Cloud security best practices. Tfsec identifies issues like unencrypted storage resources, overly permissive security groups, and missing logging configurations. Its speed and accuracy make it ideal for integration into CI/CD pipelines and pre-commit hooks.

# Example Terraform code with security issues tfsec would identify
resource "aws_s3_bucket" "insecure_bucket" {
  bucket = "my-application-data"
  acl    = "public-read"  # tfsec: S3 bucket should not be publicly readable
}

resource "aws_db_instance" "insecure_database" {
  allocated_storage    = 20
  engine              = "mysql"
  instance_class      = "db.t3.micro"
  name                = "mydatabase"
  username            = "admin"
  password            = "changeme123"  # tfsec: Database password should not be hardcoded
  skip_final_snapshot = true
  publicly_accessible = true  # tfsec: Database should not be publicly accessible
}

resource "aws_security_group" "overly_permissive" {
  name = "web-server-sg"
  
  ingress {
    from_port   = 0
    to_port     = 65535
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]  # tfsec: Security group allows unrestricted ingress
  }
}

Checkov provides another powerful option for Terraform security scanning, supporting multiple IaC formats beyond just Terraform. Its extensive policy library covers CIS benchmarks, PCI-DSS requirements, and general security best practices. Checkov's graph-based analysis understands resource relationships, enabling it to detect complex vulnerabilities that require understanding multiple resource configurations.