RDS database clusters should use a custom administrator username¶

This control checks whether an AWS RDS database cluster has changed the admin username from its default value. This rule will fail if the admin username is set to the default value.

How to fix¶

Attribute master_username of aws_rds_cluster must be non-empty.

Implementation options¶

Choose the option that matches how you manage Terraform. All options satisfy this control.

Option 1: Compliance.tf module (recommended)¶

Use the compliance.tf registry module to get this control enforced by default. This control is mapped to the frameworks shown in the tabs above. To begin, see get started with compliance.tf.

module "rds_aurora" {
  source  = "nistcsfv11.compliance.tf/terraform-aws-modules/rds-aurora/aws"
  version = ">=10.0.0,<11.0.0"

  engine         = "aurora-postgresql"
  engine_version = "16.1"
  instances = {
    one = {
      instance_class = "db.r6g.large"
    }
  }
  master_username = "root"
  name            = "abc123"
  subnets         = []
  vpc_id          = ""
}

module "rds_aurora" {
  source  = "pcidssv321.compliance.tf/terraform-aws-modules/rds-aurora/aws"
  version = ">=10.0.0,<11.0.0"

  engine         = "aurora-postgresql"
  engine_version = "16.1"
  instances = {
    one = {
      instance_class = "db.r6g.large"
    }
  }
  master_username = "root"
  name            = "abc123"
  subnets         = []
  vpc_id          = ""
}

Option 2: Open source module (terraform-aws-modules)¶

If you use terraform-aws-modules/rds-aurora/aws, configure the required module inputs to satisfy this control. You can later migrate to the compliance.tf module with minimal changes because it is compatible by design.

module "rds_aurora" {
  source  = "terraform-aws-modules/rds-aurora/aws"
  version = ">=10.0.0,<11.0.0"

  engine         = "aurora-postgresql"
  engine_version = "16.1"
  instances = {
    one = {
      instance_class = "db.r6g.large"
    }
  }
  master_username = "root"
  name            = "abc123"
  subnets         = []
  vpc_id          = ""
}

Option 3: Terraform AWS provider resources¶

If you manage resources directly, configure the relevant Terraform AWS provider resources to meet this control. See docs for the resources involved: aws_rds_cluster.

resource "aws_rds_cluster" "this" {
  backtrack_window                = 72
  cluster_identifier              = "pofix-example-cluster"
  enabled_cloudwatch_logs_exports = ["audit", "postgresql"]
  engine                          = "aurora-mysql"
  master_password                 = "ChangeMe123!"
  master_username                 = "dbadmin"
}

Tool mappings¶

Use these identifiers to cross-reference this control across tools, reports, and evidence.

• Compliance.tf (CTF) Control: rds_db_cluster_no_default_admin_name

• AWS Config Managed Rule: RDS_CLUSTER_DEFAULT_ADMIN_CHECK

• Powerpipe Control: aws_compliance.control.rds_db_cluster_no_default_admin_name