RDS DB instances should prohibit public access¶

Manage access to resources in the AWS Cloud by ensuring that AWS Relational Database Service (AWS RDS) instances are not public.

How to fix¶

Attribute publicly_accessible of aws_db_instance must be false.

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.

ACSC Essential EightAWS Control Tower GuardrailsTitle 21 CFR Part 11CIS AWS Benchmark v5.0.0CIS AWS Benchmark v6.0.0CIS Controls v8.0 IG1CISA Cyber EssentialsFedRAMP Low Baseline Rev 4FedRAMP Moderate Baseline Rev 4FFIEC Cybersecurity Assessment ToolHIPAA Omnibus Rule 2013HIPAA Security Rule 2003NIST SP 800-171 Rev 2NIST SP 800-53 Rev 4NIST SP 800-53 Rev 5NIST Cybersecurity Framework v1.1NYDFS Cybersecurity RegulationPCI DSS v3.2.1PCI DSS v4.0RBI Cyber Security Framework for UCBsRBI IT Framework for NBFCsSOC 2

module "rds" {
  source  = "acscessentialeight.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "awscontroltower.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "cfrpart11.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "cisv500.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "cisv600.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "cisv80ig1.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "cisacyberessentials.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "fedramplow.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "fedrampmoderate.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "ffiec.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "hipaa.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "hipaasecurity2003.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "nist800171.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "nist80053rev4.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "nist80053.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "nistcsfv11.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "nydfs23.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "pcidssv321.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "pcidss.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "rbicybersecurity.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "rbiitfnbfc.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

module "rds" {
  source  = "soc2.compliance.tf/terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

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

If you use terraform-aws-modules/rds/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" {
  source  = "terraform-aws-modules/rds/aws"
  version = ">=7.0.0"

  allocated_storage      = 20
  db_name                = "myapp"
  db_subnet_group_name   = "example-db-subnet-group"
  engine                 = "postgres"
  engine_version         = "16.1"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  password               = "change-me-in-production"
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]

  publicly_accessible = false
}

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_db_instance.

resource "aws_db_instance" "this" {
  allocated_storage               = 20
  enabled_cloudwatch_logs_exports = ["general", "slowquery"]
  engine                          = "mysql"
  identifier                      = "pofix-example-db"
  instance_class                  = "db.t3.micro"
  monitoring_interval             = 60
  monitoring_role_arn             = "arn:aws:iam::123456789012:role/example-role"
  password                        = "ChangeMe123!"
  skip_final_snapshot             = true
  username                        = "dbadmin"

  publicly_accessible = false
}

Which option should I choose?

Compliance.tf module (recommended): controls enforced by default and mapped to frameworks.
Open source module (terraform-aws-modules): compatible by design with compliance.tf. Same variable names for an easy, low-change migration path when you are ready.
Terraform AWS provider resources: manage Terraform resources directly.

Tool mappings¶

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

Compliance.tf (CTF) Control: rds_db_instance_prohibit_public_access
AWS Config Managed Rule: RDS_INSTANCE_PUBLIC_ACCESS_CHECK
Checkov Check: CKV_AWS_17
Powerpipe Controls: aws_compliance.control.cis_v500_2_2_3, aws_compliance.control.cis_v600_3_2_3, aws_compliance.control.rds_db_instance_prohibit_public_access