Implementing AWS Shield for DDoS protection involves several steps to ensure your AWS resources are protected against Distributed Denial of Service (DDoS) attacks. AWS Shield is a managed service that provides automatic inline mitigation capabilities to minimize application downtime and latency.

Understanding AWS Shield Tiers

Before implementation, understand the two tiers of AWS Shield:

• AWS Shield Standard: Automatically protects all AWS customers at no additional cost. It provides protection against most common, frequently occurring network and transport layer DDoS attacks.
• AWS Shield Advanced: Offers enhanced protections for higher risk applications. It provides additional detection and mitigation against larger and more sophisticated DDoS attacks, includes cost protection, and offers access to the AWS DDoS Response Team (DRT).

Decide which tier of AWS Shield is appropriate for your needs.

Activating AWS Shield Advanced (if applicable)

If AWS Shield Standard’s protection is insufficient, follow these steps to activate AWS Shield Advanced:

1. Sign into the AWS Management Console: Go to the AWS Management Console and log in with your account credentials.
2. Navigate to AWS Shield: In the AWS Management Console, locate the AWS Shield service.
3. Subscribe to AWS Shield Advanced: Follow the prompts to enable AWS Shield Advanced for your account. Understand that additional charges apply.
4. Select Resources: Choose the resources you want to protect with AWS Shield Advanced (e.g., Amazon CloudFront distributions, Elastic Load Balancers, Amazon Route 53 hosted zones, AWS Global Accelerator).
5. Configure Access for DRT: Grant the AWS DDoS Response Team (DRT) access to your AWS account to assist during high-severity DDoS attacks.

Configuring AWS WAF (Web Application Firewall)

AWS Shield Advanced integrates with AWS WAF. Configure AWS WAF to further protect your applications:

1. Create a Web ACL: Go to the AWS WAF & AWS Shield Console and create a new Web ACL to define your desired rules.
2. Add Rules and Rule Groups: Create rules or add managed rule groups that match known attack vectors and set actions like “allow,” “block,” or “count.”
3. Associate Resources: Associate the Web ACL with AWS Shield Advanced protected resources.

Implementing Rate-based Rules

Rate-based rules in AWS WAF help to protect against web request floods:

• Define Rate Limits: Create rate-based rules to specify the number of requests a client can make to your web application in a five-minute period.
• Integrate Rules: Add these rules to your Web ACL to automatically block IP addresses sourcing an excessive number of requests.

Customizing DDoS Protections

AWS Shield Advanced users have the option to customize their protections:

• Fine-tune Protections: Contact the AWS DDoS Response Team to help fine-tune DDoS protections based on your application’s traffic patterns.
• Set up Application Layer Monitoring: Utilize AWS WAF full logs and Amazon CloudWatch to monitor application layer traffic and detect anomalies.

Monitoring and Responding to DDoS Attacks

• Utilize CloudWatch Alarms: Set up alarms to notify you of potential DDoS activity based on Amazon CloudWatch metrics provided by AWS Shield.
• Real-time Metrics: AWS Shield Advanced provides real-time visibility into attacks via the AWS Management Console.
• Incident Response: In the event of an attack, you can engage with the AWS DDoS Response Team if you have AWS Shield Advanced.

Regularly Reviewing and Updating Protections

• Security Audits: Regularly audit your AWS WAF and AWS Shield configurations to ensure they align with the current threat landscape and your web application’s architecture.
• Update Rules: Keep the rules updated based on emerging threats and false positives/negatives encountered.
• Cost Management: With AWS Shield Advanced, regularly review DDoS cost protection features to understand what costs might be covered in the event of an attack.

Documentation and Best Practices

• AWS Documentation: Refer to AWS Documentation for detailed guidelines on configuring AWS Shield and AWS WAF.
• Compliance: Ensure your implementation complies with any relevant regulations and industry standards.

By following these steps, you’ll have implemented AWS Shield for DDoS protection, reducing the likelihood and impact of attacks on your AWS-deployed infrastructure. Remember to continually revisit your DDoS mitigation strategies to adapt to new threats and changes in your application architecture.