Implementing AWS Macie For Data Classification

Implementing AWS Macie for Data Classification

Overview

Amazon Macie is a fully managed data security and privacy service that uses machine learning and pattern matching to discover and protect sensitive data in Amazon S3. Macie automatically evaluates your S3 bucket inventory on a daily basis and identifies objects containing PII, financial information, credentials, and other sensitive data types. It provides two discovery approaches: automated sensitive data discovery for broad visibility and targeted discovery jobs for deep analysis.

When to Use

• When deploying or configuring implementing aws macie for data classification capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Common Misconfigurations & Verification

• Automated discovery never enabled: enabling Macie (enable-macie) does NOT start scanning. Run update-automated-discovery-configuration --status ENABLED and confirm with get-automated-discovery-configuration (must return status: ENABLED).
• Customer-managed CMK objects silently skipped: Macie cannot read objects encrypted with a customer-managed KMS key unless its service-linked role is granted kms:Decrypt. Such objects appear under unclassifiableObjectCount, not as findings. Check: aws macie2 describe-buckets --query 'buckets[?unclassifiableObjectCount.total>0].[bucketName,unclassifiableObjectCount.total]'.
• Job scoping excludes real data: an OBJECT_EXTENSION/OBJECT_KEY scope term that omits the actual prefixes/extensions means the job runs but classifies nothing. Verify the job actually processed objects via list-classification-jobs --query 'items[].statistics'.
• Findings lost after 90 days: sensitive-data findings auto-expire and are not retained unless you set an S3 export. Confirm aws macie2 get-classification-export-configuration returns a destination bucket + KMS key.
• Security Hub integration assumed: findings only flow to Security Hub if both services are enabled in the same region; check findingPublishingFrequency and that Security Hub shows the Macie product.
• Multi-account gaps: new org accounts are not auto-covered. After enable-organization-admin-account, set auto-enable and confirm members with list-members --query 'members[?relationshipStatus!=Enabled]'.

aws macie2 get-macie-session --query 'status'                 # ENABLED
aws macie2 get-automated-discovery-configuration              # status ENABLED
aws macie2 get-classification-export-configuration            # s3Destination set

Prerequisites

• AWS account with S3 buckets containing data to classify
• IAM permissions for Macie service configuration
• AWS Organizations setup (for multi-account deployment)
• S3 buckets in supported regions

Enable Macie

Via AWS CLI

# Enable Macie in the current account/region
aws macie2 enable-macie

# Verify Macie is enabled
aws macie2 get-macie-session

# Enable automated sensitive data discovery
aws macie2 update-automated-discovery-configuration \
  --status ENABLED

Via Terraform

resource "aws_macie2_account" "main" {}

resource "aws_macie2_classification_export_configuration" "main" {
  depends_on = [aws_macie2_account.main]

  s3_destination {
    bucket_name = aws_s3_bucket.macie_results.id
    key_prefix  = "macie-findings/"
    kms_key_arn = aws_kms_key.macie.arn
  }
}

Configure Discovery Jobs

Create a classification job for specific buckets

aws macie2 create-classification-job \
  --job-type ONE_TIME \
  --name "pii-scan-production-buckets" \
  --s3-job-definition '{
    "bucketDefinitions": [{
      "accountId": "123456789012",
      "buckets": [
        "production-data-bucket",
        "customer-records-bucket"
      ]
    }]
  }' \
  --managed-data-identifier-selector ALL

Create a scheduled recurring job

aws macie2 create-classification-job \
  --job-type SCHEDULED \
  --name "weekly-sensitive-data-scan" \
  --schedule-frequency-details '{
    "weekly": {
      "dayOfWeek": "MONDAY"
    }
  }' \
  --s3-job-definition '{
    "bucketDefinitions": [{
      "accountId": "123456789012",
      "buckets": ["all-data-bucket"]
    }],
    "scoping": {
      "includes": {
        "and": [{
          "simpleScopeTerm": {
            "comparator": "STARTS_WITH",
            "key": "OBJECT_KEY",
            "values": ["uploads/", "documents/"]
          }
        }]
      }
    }
  }'

Custom Data Identifiers

Create a custom identifier for internal IDs

aws macie2 create-custom-data-identifier \
  --name "internal-employee-id" \
  --description "Matches internal employee ID format EMP-XXXXXX" \
  --regex "EMP-[0-9]{6}" \
  --severity-levels '[
    {"occurrencesThreshold": 1, "severity": "LOW"},
    {"occurrencesThreshold": 10, "severity": "MEDIUM"},
    {"occurrencesThreshold": 50, "severity": "HIGH"}
  ]'

Create identifier for project codes

aws macie2 create-custom-data-identifier \
  --name "project-code-identifier" \
  --description "Matches project codes in format PRJ-XXXX-XX" \
  --regex "PRJ-[A-Z]{4}-[0-9]{2}" \
  --keywords '["project", "code", "initiative"]' \
  --maximum-match-distance 50

Allow Lists

Create an allow list to suppress false positives

aws macie2 create-allow-list \
  --name "test-data-exclusions" \
  --description "Exclude known test data patterns" \
  --criteria '{
    "regex": "TEST-[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{4}"
  }'

Managed Data Identifiers

Macie provides 300+ managed data identifiers covering:

Findings Management

List findings

# Get sensitive data findings
aws macie2 list-findings \
  --finding-criteria '{
    "criterion": {
      "severity.description": {
        "eq": ["High"]
      },
      "category": {
        "eq": ["CLASSIFICATION"]
      }
    }
  }' \
  --sort-criteria '{"attributeName": "updatedAt", "orderBy": "DESC"}' \
  --max-results 25

Get finding details

aws macie2 get-findings \
  --finding-ids '["finding-id-1", "finding-id-2"]'

Export findings to Security Hub

# Macie automatically publishes findings to Security Hub
# Verify integration:
aws macie2 get-macie-session --query 'findingPublishingFrequency'

EventBridge Integration for Automated Response

{
  "source": ["aws.macie"],
  "detail-type": ["Macie Finding"],
  "detail": {
    "severity": {
      "description": ["High", "Critical"]
    }
  }
}

Lambda function for automated remediation

import boto3
import json

s3 = boto3.client('s3')
sns = boto3.client('sns')

def lambda_handler(event, context):
    finding = event['detail']
    severity = finding['severity']['description']
    bucket = finding['resourcesAffected']['s3Bucket']['name']
    key = finding['resourcesAffected']['s3Object']['key']
    sensitive_types = [d['type'] for d in finding.get('classificationDetails', {}).get('result', {}).get('sensitiveData', [])]

    if severity in ['High', 'Critical']:
        # Tag the object for review
        s3.put_object_tagging(
            Bucket=bucket,
            Key=key,
            Tagging={
                'TagSet': [
                    {'Key': 'macie-finding', 'Value': severity},
                    {'Key': 'sensitive-data', 'Value': ','.join(sensitive_types)},
                    {'Key': 'requires-review', 'Value': 'true'}
                ]
            }
        )

        # Notify security team
        sns.publish(
            TopicArn='arn:aws:sns:us-east-1:123456789012:security-alerts',
            Subject=f'Macie {severity} Finding: {bucket}/{key}',
            Message=json.dumps({
                'bucket': bucket,
                'key': key,
                'severity': severity,
                'sensitive_data_types': sensitive_types,
                'finding_id': finding['id']
            }, indent=2)
        )

    return {'statusCode': 200}

Multi-Account Deployment

Designate Macie administrator account

# From the management account
aws macie2 enable-organization-admin-account \
  --admin-account-id 111111111111

Add member accounts

# From the administrator account
aws macie2 create-member \
  --account '{"accountId": "222222222222", "email": "security@example.com"}'

Monitoring Macie Operations

Usage statistics

aws macie2 get-usage-statistics \
  --filter-by '[{"comparator": "GT", "key": "accountId", "values": []}]' \
  --sort-by '{"key": "accountId", "orderBy": "ASC"}'

Classification job status

aws macie2 list-classification-jobs \
  --filter-criteria '{"includes": [{"comparator": "EQ", "key": "jobStatus", "values": ["RUNNING"]}]}'

References

• AWS Macie Documentation: https://docs.aws.amazon.com/macie/
• AWS Macie Pricing
• Supported File Types for Macie Analysis
• GDPR and CCPA Compliance with Macie