For AI agents: A markdown version of this page is available at https://docs.datadoghq.com/security/code_security/iac_security/iac_rules/cloudformation-aws-emr-wihout-vpc.md. A documentation index is available at /llms.txt.

EMR without VPC

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Metadata

Id: cloudformation-aws-emr-wihout-vpc

Provider: AWS

Platform: CloudFormation

Severity: Low

Category: Networking and Firewall

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Description

EMR clusters must be launched inside a VPC to ensure network isolation and to allow enforcement of security controls such as security groups, private subnet routing, and network ACLs. Omitting a VPC subnet can make cluster nodes publicly reachable or prevent VPC-level access restrictions.

In CloudFormation, AWS::EMR::Cluster resources must define either Properties.Instances.Ec2SubnetId (single subnet) or Properties.Instances.Ec2SubnetIds (list of subnets) with non-null values. Resources missing both properties or containing null or empty values will be flagged.

Secure configuration example:

MyEMRCluster:
  Type: AWS::EMR::Cluster
  Properties:
    Name: my-emr-cluster
    ReleaseLabel: emr-6.10.0
    Instances:
      Ec2SubnetId: !Ref MyPrivateSubnet
      MasterInstanceGroup:
        InstanceCount: 1
        InstanceType: m5.xlarge
      CoreInstanceGroup:
        InstanceCount: 2
        InstanceType: m5.xlarge
    ServiceRole: !Ref EMRServiceRole
    JobFlowRole: !Ref EMRInstanceProfile

Compliant Code Examples

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  CustomAmiId:
    Type: String
  InstanceType:
    Type: String
  ReleaseLabel:
    Type: String
  SubnetId:
    Type: String
  TerminationProtected:
    Type: String
    Default: 'false'
  ElasticMapReducePrincipal:
    Type: String
  Ec2Principal:
    Type: String
Resources:
  cluster:
    Type: AWS::EMR::Cluster
    Properties:
      CustomAmiId: !Ref CustomAmiId
      Instances:
        MasterInstanceGroup:
          InstanceCount: 1
          InstanceType: !Ref InstanceType
          Market: ON_DEMAND
          Name: cfnMaster
        CoreInstanceGroup:
          InstanceCount: 1
          InstanceType: !Ref InstanceType
          Market: ON_DEMAND
          Name: cfnCore
        TerminationProtected: !Ref TerminationProtected
        Ec2SubnetId: !Ref SubnetId
      Name: CFNtest
      JobFlowRole: !Ref emrEc2InstanceProfile
      ServiceRole: !Ref emrRole
      ReleaseLabel: !Ref ReleaseLabel
      VisibleToAllUsers: true
      Tags:
        - Key: key1
          Value: value1
  emrRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2008-10-17
        Statement:
          - Sid: ''
            Effect: Allow
            Principal:
              Service: !Ref ElasticMapReducePrincipal
            Action: 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonElasticMapReduceRole'
  emrEc2Role:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2008-10-17
        Statement:
          - Sid: ''
            Effect: Allow
            Principal:
              Service: !Ref Ec2Principal
            Action: 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonElasticMapReduceforEC2Role'
  emrEc2InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref emrEc2Role

Non-Compliant Code Examples

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  CustomAmiId:
    Type: String
  InstanceType:
    Type: String
  ReleaseLabel:
    Type: String
  SubnetId:
    Type: String
  TerminationProtected:
    Type: String
    Default: 'false'
  ElasticMapReducePrincipal:
    Type: String
  Ec2Principal:
    Type: String
Resources:
  cluster:
    Type: AWS::EMR::Cluster
    Properties:
      CustomAmiId: !Ref CustomAmiId
      Instances:
        MasterInstanceGroup:
          InstanceCount: 1
          InstanceType: !Ref InstanceType
          Market: ON_DEMAND
          Name: cfnMaster
        CoreInstanceGroup:
          InstanceCount: 1
          InstanceType: !Ref InstanceType
          Market: ON_DEMAND
          Name: cfnCore
        TerminationProtected: !Ref TerminationProtected
      Name: CFNtest
      JobFlowRole: !Ref emrEc2InstanceProfile
      ServiceRole: !Ref emrRole
      ReleaseLabel: !Ref ReleaseLabel
      VisibleToAllUsers: true
      Tags:
        - Key: key1
          Value: value1
  emrRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2008-10-17
        Statement:
          - Sid: ''
            Effect: Allow
            Principal:
              Service: !Ref ElasticMapReducePrincipal
            Action: 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonElasticMapReduceRole'
  emrEc2Role:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2008-10-17
        Statement:
          - Sid: ''
            Effect: Allow
            Principal:
              Service: !Ref Ec2Principal
            Action: 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonElasticMapReduceforEC2Role'
  emrEc2InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
        - !Ref emrEc2Role