Sample Autonomous Threat Identification and Mitigation in AWS (Sample)

Estimated reading time: 4 minutes

This sample outlines a conceptual architecture and key AWS services for building an Autonomous Threat Identification and Mitigation system, focusing on detecting and responding to suspicious network traffic.

Conceptual Architecture

        
+-----------------+     +-----------------+       +---------------------+     +---------------------+     +---------------------+
| Network Traffic | --> | VPC Flow Logs /   | --> | Amazon Kinesis Data | --> | AWS Lambda Function | --> | AWS Security Group  |
| (e.g., EC2)     |     | GuardDuty Findings|     | Streams             |     | (Threat Detection   |     | (Automated Rule     |
+-----------------+     +-----------------+       +---------------------+     | & Mitigation Logic) |     | Modification)       |
                                                                              +---------------------+     +---------------------+
                                                                                      |
                                                                                      v
                                                                              +-------------------------+
                                                                              | Amazon SNS (Alerting)   |
                                                                              +-------------------------+
        
    

Explanation of Components

• Network Traffic (e.g., EC2 Instances): Represents the network traffic within your AWS Virtual Private Cloud (VPC) that you want to monitor.
• VPC Flow Logs / GuardDuty Findings:
  • VPC Flow Logs: Capture information about the IP traffic going to and from network interfaces in your VPC. Configure these to send data to Amazon S3 or directly to Kinesis Data Streams.
  • Amazon GuardDuty: A threat detection service that continuously monitors for malicious activity and unauthorized behavior. Findings can indicate potential threats.
• Amazon Kinesis Data Streams: A scalable and durable real-time data streaming service used to ingest and process the continuous stream of VPC Flow Logs or GuardDuty findings.
• AWS Lambda Function (Threat Detection and Mitigation Logic): A serverless compute service that runs your custom code. It consumes data from Kinesis, implements threat detection logic, and performs mitigation actions.
• AWS Security Group (Automated Rule Modification): Acts as a virtual firewall for your EC2 instances. The Lambda function can programmatically modify its rules to block malicious traffic.
• Amazon SNS (Alerting): A messaging service to send notifications (e.g., email, SMS) to security teams when a threat is detected and mitigated.

Conceptual Implementation Steps

1. Enable VPC Flow Logs or Amazon GuardDuty: Configure VPC Flow Logs for relevant VPCs or enable Amazon GuardDuty in your account.
2. Create a Kinesis Data Stream: If using VPC Flow Logs directly, create a Kinesis Data Stream.
3. Write the AWS Lambda Function:
   • Permissions: Grant necessary IAM permissions (e.g., kinesis:*, ec2:ModifySecurityGroupRules, sns:Publish).
   • Code Logic (Python Example – Conceptual):

                             
     import json
     import boto3
     
     ec2 = boto3.client('ec2')
     sns = boto3.client('sns')
     SECURITY_GROUP_ID = 'sg-xxxxxxxxxxxxxxxxx' # Replace with your Security Group ID
     SNS_TOPIC_ARN = 'arn:aws:sns:us-east-1:123456789012:ThreatAlerts' # Replace with your SNS Topic ARN
     
     def lambda_handler(event, context):
         for record in event['Records']:
             payload = json.loads(record['kinesis']['data']) if 'kinesis' in record else record # Handle Kinesis or other event sources
     
             # --- Threat Detection Logic ---
             suspicious_ip = None
             if 'log-stream-name' in payload: # Example for VPC Flow Logs
                 log_events = payload.get('logEvents', [])
                 for log_event in log_events:
                     log_message = log_event['message']
                     if "MALICIOUS_IP_PATTERN" in log_message: # Replace with your detection pattern
                         # Extract the malicious IP address from the log message
                         suspicious_ip = log_message.split(" ")[5] # Example - adjust based on your log format
                         break
             elif 'detail-type' in payload and payload['detail-type'] == "GuardDuty Finding": # Example for GuardDuty
                 finding = payload['detail']['finding']
                 if finding['severity'] >= 7.0 and finding['resource']['resourceType'] == 'EC2Instance':
                     for ip_set in finding['network']['remoteIpDetails']['ipAddressV4']:
                         suspicious_ip = ip_set['ipAddressV4']
                         break
     
             if suspicious_ip:
                 try:
                     # --- Mitigation Logic (Block IP in Security Group) ---
                     response = ec2.authorize_security_group_ingress(
                         GroupId=SECURITY_GROUP_ID,
                         IpPermissions=[
                             {
                                 'IpProtocol': 'all',
                                 'IpRanges': [{'CidrIp': f'{suspicious_ip}/32'}]
                             }
                         ]
                     )
                     print(f"Blocked suspicious IP: {suspicious_ip}")
     
                     # --- Send Alert ---
                     sns.publish(
                         TopicArn=SNS_TOPIC_ARN,
                         Subject='Automated Threat Mitigation Alert',
                         Message=f'Detected and blocked suspicious IP address: {suspicious_ip} on Security Group: {SECURITY_GROUP_ID}'
                     )
     
                 except Exception as e:
                     print(f"Error during mitigation: {e}")
     
         return {
             'statusCode': 200,
             'body': json.dumps('Processed events!')
         }
                             
                         

4. Configure Event Source for Lambda: Set up a Kinesis trigger or an EventBridge trigger (for GuardDuty) for your Lambda function.
5. Set up Amazon SNS Topic: Create an SNS topic and subscribe relevant recipients for alerts.

Important Considerations and Next Steps

• Threat Detection Logic: This is crucial and depends on your specific security needs.
• Mitigation Strategies: Blocking IPs is a basic example; more advanced actions are possible.
• Error Handling and Logging: Implement robust error handling using CloudWatch Logs.
• Scalability and Performance: Ensure your AWS services can handle the expected data volume.
• Security Best Practices: Follow IAM best practices for least privilege.
• Testing: Thoroughly test in a non-production environment.
• Integration with Other Security Tools: Consider integrating with other AWS or third-party security services.

This sample provides a foundational understanding. Adapt and expand it based on your specific environment and requirements.