domain-protect

scans Amazon Route53 across an AWS Organization for domain records vulnerable to takeover

deploy to security audit account

scan your entire AWS Organization

receive alerts by Slack or email

or manually scan from your laptop

subdomain detection functionality

• scans Amazon Route53 Alias records to identify CloudFront distributions with missing S3 origin
• scans Amazon Route53 CNAME records to identify CloudFront distributions with missing S3 origin
• scans Amazon Route53 for ElasticBeanstalk Alias records vulnerable to takeover
• scans Amazon Route53 for ElasticBeanstalk CNAMES vulnerable to takeover
• scans Amazon Route53 for subdomain NS delegations vulnerable to takeover
• scans Amazon Route53 for S3 Alias records vulnerable to takeover
• scans Amazon Route53 for S3 CNAMES vulnerable to takeover
• scans Amazon Route53 to discover vulnerable CNAME records for Azure resources
• scans Amazon Route53 to discover vulnerable CNAME records for Google Cloud resources

options

1. scheduled lambda functions with email and Slack alerts, across an AWS Organization, deployed using Terraform
2. manual scans run from your laptop or CloudShell, in a single AWS account

notifications

• Slack channel notification per vulnerability type, listing account names and vulnerable domains
• Email notification in JSON format with account names, account IDs and vulnerable domains by subscribing to SNS topic

requirements

• Security audit account within AWS Organizations
• Security audit read-only role with an identical name in every AWS account of the Organization
• Storage bucket for Terraform state file
• Terraform 1.0.x

usage

• replace the Terraform state S3 bucket fields in the command below as appropriate
• for local testing, duplicate terraform.tfvars.example, rename without the .example suffix
• enter details appropriate to your organization and save
• alternatively enter Terraform variables within your CI/CD pipeline

terraform init -backend-config=bucket=TERRAFORM_STATE_BUCKET -backend-config=key=TERRAFORM_STATE_KEY -backend-config=region=TERRAFORM_STATE_REGION
terraform workspace new dev
terraform plan
terraform apply

AWS IAM policies

For least privilege access control, example AWS IAM policies are provided:

• domain-protect audit policy - attach to domain-protect audit role in every AWS account
• domain-protect deploy policy - attach to IAM group or role assumed by CI/CD pipeline

adding new checks

• create a new subdirectory within the terraform-modules/lambda/code directory
• add Python code file with same name as the subdirectory
• add the name of the file without extension to var.lambdas in variables.tf
• add a subdirectory within the terraform-modules/lambda/build directory, following the existing naming pattern
• add a .gitkeep file into the new directory
• update the .gitignore file following the pattern of existing directories
• apply Terraform

adding notifications to extra Slack channels

• add an extra channel to your slack_channels variable list
• add an extra webhook URL or repeat the same webhook URL to your slack_webhook_urls variable list
• apply Terraform

testing

• use multiple Terraform workspace environments, e.g. dev, prd
• use the slack_channels_dev variable for your dev environment to notify a test Slack channel
• for new subdomain takeover categories, create correctly configured and vulnerable domain names in Route53
• minimise the risk of malicious takeover by using a test domain, with domain names which are hard to enumerate
• remove any vulnerable domains as soon as possible

ci/cd

• infrastructure has been deployed using CircleCI
• environment variables to be entered in CircleCI project settings:

• to validate an updated CircleCI configuration:

docker run -v `pwd`:/whatever circleci/circleci-cli circleci config validate /whatever/.circleci/config.yml

limitations

• this tool cannot guarantee 100% protection against subdomain takeover
• it currently only scans Amazon Route53, and only checks a limited number of takeover types