Default VPC Exists

• Query id: 96ed3526-0179-4c73-b1b2-372fde2e0d13
• Query name: Default VPC Exists
• Platform: Terraform
• Severity: Medium
• Category: Insecure Defaults
• URL: Github

Description

It isn't recommended to use resources in default VPC
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "aws_default_vpc" "positive1" {
  tags = {
    Name = "Default VPC"
  }
}

Positive test num. 2 - tf file

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "3.7.0"

  name = "my-vpc"
  cidr = "10.0.0.0/16"

  azs             = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24", "10.0.103.0/24"]

  enable_nat_gateway = true
  enable_vpn_gateway = true
  default_vpc_name   = "my-default-vpc"

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "aws_vpc" "negative1" {
  cidr_block       = "10.0.0.0/16"
  instance_tenancy = "default"

  tags = {
    Name = "main"
  }
}

Negative test num. 2 - tf file

module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "3.7.0"

  name = "my-vpc"
  cidr = "10.0.0.0/16"

  azs             = ["eu-west-1a", "eu-west-1b", "eu-west-1c"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24", "10.0.103.0/24"]

  enable_nat_gateway = true
  enable_vpn_gateway = true

  tags = {
    Terraform   = "true"
    Environment = "dev"
  }
}