AWSTemplateFormatVersion: 2010-09-09
Description: This Template will create the supporting infrastructure for the Prowler Fargate AWS Security Blog Post
Parameters:
  ProwlerClusterName:
    Type: String
    Description: Name of the ECS Cluster that the Prowler Fargate Task will run in
    Default: ProwlerCluster
  ProwlerContainerName: 
    Type: String
    Description: Name of the Prowler Container Definition within the ECS Task
    Default: prowler
  ProwlerContainerInfo: 
    Type: String
    Description: ECR URI of the Prowler container
  ProwlerExecutionRole:
    Type: String
    Description: ARN of the IAM Task Execution Role ECS uses to pull images from ECR and send logs to CloudWatch
  ProwlerTaskRole:
    Type: String
    Description: ARN of the Task IAM Role that gives Prowler permissions to perform its checks
  ProwlerSecurityGroup:
    Type: String
    Description: Security Group that allows at least HTTPS 443 inbound/outbound
  ProwlerScheduledSubnet1:
    Type: String
    Description: Subnet Id in which Prowler can be scheduled to Run
  ProwlerScheduledSubnet2:
    Type: String
    Description: A secondary Subnet Id in which Prowler can be scheduled to Run 
Resources:
  ProwlerReportDynamoDBTable: 
    Type: AWS::DynamoDB::Table
    Properties: 
      AttributeDefinitions: 
        - 
          AttributeName: "NOTES"
          AttributeType: "S"
      KeySchema: 
        - 
          AttributeName: "NOTES"
          KeyType: "HASH"
      ProvisionedThroughput: 
        ReadCapacityUnits: "50"
        WriteCapacityUnits: "50"
      TableName: !Sub 'prowler-report-table-${AWS::AccountId}'
      StreamSpecification:
        StreamViewType: NEW_IMAGE
  ProwlerECSCloudWatchLogsGroup:
    Type: AWS::Logs::LogGroup
    Properties: 
      LogGroupName: !Join [ "-", [ !Ref ProwlerContainerName, !Ref 'AWS::StackName' ] ]
      RetentionInDays: 90
  ProwlerECSCluster:
    Type: AWS::ECS::Cluster
    Properties: 
      ClusterName: !Ref ProwlerClusterName
  ProwlerECSTaskDefinition:
    Type: AWS::ECS::TaskDefinition
    Properties: 
      ContainerDefinitions: 
        -   
          Image: !Ref ProwlerContainerInfo
          Name: !Ref ProwlerContainerName
          Environment:
            - Name: MY_DYANMODB_TABLE
              Value: !Ref ProwlerReportDynamoDBTable
          LogConfiguration:
            LogDriver: awslogs
            Options:
              awslogs-group: !Ref ProwlerECSCloudWatchLogsGroup
              awslogs-region: !Ref 'AWS::Region'
              awslogs-stream-prefix: ecs
      Cpu: 2048
      ExecutionRoleArn: !Ref ProwlerExecutionRole
      Memory: 4096
      NetworkMode: awsvpc
      TaskRoleArn: !Ref ProwlerTaskRole
      Family: Prowler2SecurityHubTask
      RequiresCompatibilities:
        - FARGATE
  ProwlerTaskScheduler:
    Type: AWS::Events::Rule
    Properties:
      ScheduleExpression: "rate(7 days)"
      State: ENABLED
      Targets:
        - Arn: !GetAtt ProwlerECSCluster.Arn
          RoleArn: !Ref ProwlerTaskRole
          Id: prowlerTaskScheduler
          EcsParameters:
            TaskDefinitionArn: !Ref ProwlerECSTaskDefinition
            TaskCount: 1
            LaunchType: FARGATE
            PlatformVersion: 'LATEST'
            NetworkConfiguration:
              AwsVpcConfiguration:
                AssignPublicIp: ENABLED
                SecurityGroups:
                  - !Ref ProwlerSecurityGroup
                Subnets:
                  - !Ref ProwlerScheduledSubnet1
                  - !Ref ProwlerScheduledSubnet2
  DynamoStreamLambdaMapping:
    Type: AWS::Lambda::EventSourceMapping
    Properties:
      BatchSize: 1
      Enabled: True
      EventSourceArn: 
        Fn::GetAtt: [ ProwlerReportDynamoDBTable , StreamArn ]
      FunctionName: 
        Fn::GetAtt: [ ProwlertoSecHubLambdaFunction , Arn ]
      StartingPosition: LATEST #always start at the tail of the stream
  ProwlertoSecHubLambdaFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: Prowler2SecurityHub
      Description: Maps Prowler findings sent from ECS to DynamoDB into the ASFF via DynamoDB Streams before importing to Security Hub
      Handler: index.lambda_handler
      MemorySize: 384
      Role: !GetAtt ProwlertoSecHubLambdaRole.Arn
      Runtime: python3.7
      Timeout: 70
      Environment:
        Variables:
          account_num: !Ref 'AWS::AccountId'
          region: !Ref 'AWS::Region'
      Code:
        ZipFile: |
          import json
          import boto3
          import datetime
          import uuid
          import os
          def lambda_handler(event, context):
              # import Lambda ENV VARs
              accountId = os.environ['account_num']
              awsRegion = os.environ['region']
              # Use Prowler finding notes for ASFF Description
              prowlerDescription = str(event['Records'][0]['dynamodb']['NewImage']['NOTES']['S'])
              # Use Prowler finding title text for ASFF Title
              prowlerTitle = str(event['Records'][0]['dynamodb']['NewImage']['TITLE_TEXT']['S'])
              # looping through Prowler score result, set severity & compliance based on finding
              prowlerResult = str(event['Records'][0]['dynamodb']['NewImage']['RESULT']['S'])
              if prowlerResult == 'PASS':
                  prowlerComplianceRating = 'PASSED'
                  prowlerProductSev = int(0)
                  prowlerProductNorm = int(0)
              elif prowlerResult == 'INFO':
                  prowlerComplianceRating = 'NOT_AVAILABLE'
                  prowlerProductSev = int(1)
                  prowlerProductNorm = int(1)
              elif prowlerResult == 'FAIL':
                  prowlerComplianceRating = 'FAILED'
                  prowlerProductSev = int(8)
                  prowlerProductNorm = int(80)
              else:
                  print("No Compliance Info Found!")
              # ISO Time
              iso8061Time = datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc).isoformat()
              # ASFF BIF Id
              asffID = str(uuid.uuid4())
              # import security hub boto3 client
              sechub = boto3.client('securityhub')
              # call BIF
              try:
                  response = sechub.batch_import_findings(
                      Findings=[
                          {
                              'SchemaVersion': '2018-10-08',
                              'Id': asffID,
                              'ProductArn': 'arn:aws:securityhub:' + awsRegion + ':' + accountId + ':product/' + accountId + '/default',
                              'ProductFields': {
                                  'ProviderName': 'Prowler',
                                  'ProviderVersion': 'v2.1.0',
                                  },
                              'GeneratorId': asffID,
                              'AwsAccountId': accountId,
                              'Types': [ 'Software and Configuration Checks' ],
                              'FirstObservedAt': iso8061Time,
                              'UpdatedAt': iso8061Time,
                              'CreatedAt': iso8061Time,
                              'Severity': {
                                  'Product': prowlerProductSev,
                                  'Normalized': prowlerProductNorm
                              },
                              'Title': prowlerTitle,
                              'Description': prowlerDescription,
                              'Resources': [
                                  {
                                      'Type': 'AwsAccount',
                                      'Id': 'AWS::::Account:' + accountId,
                                      'Partition': 'aws',
                                      'Region': awsRegion,
                                  }
                              ],
                              'WorkflowState': 'NEW',
                              'Compliance': {'Status': prowlerComplianceRating},
                              'RecordState': 'ACTIVE'
                          }
                      ]
                  )
                  print(response)
              except Exception as e:
                  print(e)
                  print("Submitting finding to Security Hub failed, please troubleshoot further")
                  raise
  ProwlertoSecHubLambdaRole:
    Type: AWS::IAM::Role
    Properties:
      Policies:
      - PolicyName: Prowler2SecurityHub-Policy
        PolicyDocument:
          Version: 2012-10-17
          Statement:
          - Effect: Allow
            Action:
            - cloudwatch:PutMetricData
            - securityhub:BatchImportFindings
            Resource: '*'
          - Effect: Allow
            Action:
            - logs:CreateLogGroup
            - logs:CreateLogStream
            - logs:PutLogEvents
            Resource: '*'
          - Effect: Allow
            Action:
            - dynamodb:GetRecords
            - dynamodb:GetShardIterator
            - dynamodb:DescribeStream
            - dynamodb:ListStreams
            Resource: !GetAtt ProwlerReportDynamoDBTable.StreamArn
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal: { Service: lambda.amazonaws.com }
          Action:
          - sts:AssumeRole
Outputs:
  ProwlerReportDynamoDBTable:
    Description: DynamoDB Table to upload ETLed Prowler findings
    Value: !Ref ProwlerReportDynamoDBTable