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RDS DB instance automatic minor version upgrade should be enabled

Minor version upgrades for RDS engines (MySQL, PostgreSQL, MariaDB, Oracle, SQL Server) include security patches, bug fixes, and performance improvements released by the engine vendor. When auto_minor_version_upgrade is disabled, your database stays on a version with known vulnerabilities until someone manually triggers the upgrade. This creates a window where publicly disclosed CVEs apply to your running instance.

Automatic minor upgrades apply during the configured maintenance window, so they don't cause surprise downtime outside that period. The operational cost of enabling this flag is low compared to the risk of running unpatched database software in production.

Retrofit consideration

Enabling auto minor version upgrade on existing instances may trigger an upgrade at the next maintenance window if a newer minor version is available. Test in staging first, particularly for engines with behavior changes between minor versions.

Implementation

Choose the approach that matches how you manage Terraform.

Use the compliance.tf module to enforce this control by default. See get started with compliance.tf.

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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}


module "rds" {
  source  = "cis.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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}


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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]
}

If you use terraform-aws-modules/rds/aws, set the right module inputs for 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                 = "mysql"
  engine_version         = "8.0.41"
  family                 = "mysql8.0"
  identifier             = "abc123"
  instance_class         = "db.t3.micro"
  major_engine_version   = "8.0"
  password_wo            = "change-me-in-production"
  skip_final_snapshot    = true
  username               = "dbadmin"
  vpc_security_group_ids = ["sg-12345678"]

  auto_minor_version_upgrade = true
}

Use AWS provider resources directly. 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-abc123"
  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"

  auto_minor_version_upgrade = true
}

What this control checks

For every aws_db_instance resource, auto_minor_version_upgrade must be true. The argument defaults to true in the AWS provider, so an explicit false is the primary failure case. If your module or organization template sets it to false, the control flags it. No other resources or arguments are involved. Evaluation is at plan time: true passes, false fails.

Common pitfalls

  • Default is true but can be overridden silently

    The Terraform AWS provider defaults auto_minor_version_upgrade to true on aws_db_instance. Shared modules or variable-driven configs may override this to false, and the absence of an explicit setting in your root module doesn't guarantee the module internals preserve the default. Review module inputs carefully.

  • Read replicas inherit the setting independently

    RDS read replicas created via aws_db_instance with replicate_source_db have their own auto_minor_version_upgrade attribute. A replica can have the flag set to false even if the primary has it set to true. Each instance is evaluated separately.

  • Multi-AZ failover during upgrade

    For Multi-AZ deployments, the minor version upgrade applies to the standby first, then a failover occurs, resulting in a brief outage. Teams sometimes disable auto upgrades to avoid this, but the security tradeoff rarely justifies it.

  • Aurora instances use a different resource

    Aurora DB instances use aws_rds_cluster_instance, not aws_db_instance. This control applies to non-Aurora RDS instances only. Aurora cluster-level auto minor version upgrade is a separate control (rds_db_cluster_automatic_minor_version_upgrade_enabled).

Audit evidence

An auditor expects AWS Config rule evaluation results for rds-automatic-minor-version-upgrade-enabled showing all RDS DB instances as compliant. Supporting evidence includes CLI output from aws rds describe-db-instances with "AutoMinorVersionUpgrade": true for each instance. Screenshots from the RDS Console showing 'Auto minor version upgrade' set to 'Yes' on each instance's configuration tab work as supplemental evidence.

For ongoing compliance posture, a Security Hub dashboard or CSPM report showing historical compliance status for this rule strengthens the audit trail.

Framework-specific interpretation

PCI DSS v4.0: Requirement 6.3.3 calls for installing applicable security patches and updates. Automatic minor version upgrades deliver vendor-released engine fixes during the maintenance window, which is one way to satisfy the timely remediation expectation under 6.3.

Tool mappings

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

  • Compliance.tf Control: rds_db_instance_automatic_minor_version_upgrade_enabled

  • AWS Config Managed Rule: RDS_AUTOMATIC_MINOR_VERSION_UPGRADE_ENABLED

  • Checkov Check: CKV_AWS_226

  • Powerpipe Control: aws_compliance.control.rds_db_instance_automatic_minor_version_upgrade_enabled

  • Prowler Checks: rds_cluster_minor_version_upgrade_enabled, rds_instance_minor_version_upgrade_enabled

  • AWS Security Hub Controls: RDS.13, RDS.35

  • KICS Query: 3b6d777b-76e3-4133-80a3-0d6f667ade7f

Last reviewed: 2026-03-09