AWS Shield provides a managed defense against Distributed Denial of Service (DDoS) attacks to ensure application availability and user trust. This service specifically protects cloud applications from malicious traffic floods that aim to overwhelm and disrupt global accessibility.
- Cyber Threat Mitigation: Defends globally accessible cloud applications against the increasing exposure to disruptive cyber attacks.
- DDoS Protection: Specifically targets and neutralizes flooding attacks designed to overwhelm application infrastructure and resources.
- Availability Maintenance: Safeguards the continuous operation and performance of services to prevent downtime for end-users.
- Managed Security: Provides a robust, AWS-native solution that automates the defense of applications running within the cloud environment.
AWS Shield is tightly integrated with AWS’s global infrastructure and edge network, allowing it to absorb and mitigate attacks close to their source before they reach application resources.
AWS Shield is available in two tiers, each designed to meet different security requirements.
AWS Shield Standard
AWS Shield Standard is enabled by default at no additional cost for all AWS customers. It provides automatic protection against the most common and frequently occurring DDoS attacks.
- Protects against Layer 3 (Network) and Layer 4 (Transport) attacks
- Automatically mitigates attacks such as SYN floods, UDP floods, and reflection attacks
- Integrated with AWS edge services like Amazon CloudFront and Amazon Route 53
Shield Standard is ideal for most workloads that require baseline DDoS protection without additional configuration.
AWS Shield Advanced
AWS Shield Advanced is a paid service designed for applications that require enhanced visibility, control, and support during large-scale or sophisticated DDoS attacks.
- Enhanced protection for Amazon CloudFront, Route 53, Elastic Load Balancers, and EC2 instances.
- Near real-time attack visibility and diagnostics.
- 24/7 access to the AWS Shield Response Team (SRT).
- Enhanced Application Layer Protection: Unlike the standard tier's focus on infrastructure, Shield Advanced offers sophisticated detection and automatic mitigation for Layer 7 (HTTP/HTTPS) attacks, including integration with AWS WAF at no additional cost for protected resources.
- Tailored Threat Intelligence: It uses health-based detection and machine learning to baseline your application’s specific traffic patterns, allowing it to identify and alert you to smaller, subtler anomalies that would otherwise be missed by static thresholds.
Shield Advanced is suitable for mission-critical applications with strict availability requirements.
AWS Shield Working
AWS Shield leverages AWS’s global edge network to detect and mitigate DDoS attacks early. The protection process typically works as follows:
- Incoming traffic enters the AWS edge network.
- AWS Shield continuously monitors traffic patterns using automated detection systems.
- When abnormal traffic behavior is detected, mitigation techniques are applied automatically.
- Malicious traffic is filtered or absorbed at the edge, preventing it from reaching backend resources.
- Legitimate user traffic continues to flow normally to the application.
This automated approach ensures high availability while minimizing manual intervention.
Benefits of AWS Shield
- Always-on protection: Automatically enabled without requiring user action.
- Low latency mitigation: Attacks are mitigated at AWS edge locations.
- Scalability: Designed to handle large-scale volumetric attacks.
- Operational simplicity: No infrastructure or appliances to manage.
- Deep AWS integration: Works seamlessly with AWS networking and edge services.
Common Use Cases
- Protecting public-facing websites and APIs.
- Securing e-commerce platforms against traffic floods.
- Safeguarding DNS infrastructure using Route 53.
- Defending global applications delivered via CloudFront.
- Ensuring high availability for critical workloads.
Real-World Scenario DDoS Attack Scenario and How AWS Shield Prevents It:
Imagine an e-commerce application hosted on AWS during a major sale event. The architecture uses Amazon CloudFront in front of an Application Load Balancer, with backend services running on EC2 and Lambda. DNS is managed by Amazon Route 53.
During peak traffic, attackers launch a volumetric DDoS attack, flooding the website with millions of malicious requests per second using a botnet. The goal is to exhaust network bandwidth and make the site unavailable to legitimate users.
What Happens Without AWS Shield
- The application load balancer becomes overwhelmed.
- Backend EC2 instances scale uncontrollably, increasing costs.
- Legitimate customers experience slow responses or downtime.
- Revenue and customer trust are impacted.
How AWS Shield Mitigates the Attack:
1. Traffic Hits the AWS Edge Network
All incoming traffic first reaches AWS’s global edge network through CloudFront and Route 53. This prevents malicious traffic from directly hitting backend infrastructure.
2. Automatic Detection of Abnormal Traffic
AWS Shield continuously monitors traffic patterns. It detects sudden spikes, malformed packets, and traffic signatures commonly associated with DDoS attacks such as:
- SYN floods
- UDP floods
- Reflection and amplification attacks
3. Attack Mitigation at the Edge
Once the attack is detected:
- AWS Shield automatically applies mitigation techniques.
- Malicious traffic is dropped or absorbed at edge locations.
- Legitimate user traffic is allowed to pass through normally.
This ensures backend services remain available and responsive.
4. Enhanced Protection with AWS Shield Advanced
If AWS Shield Advanced is enabled:
- Near real-time attack metrics and visibility are provided
- AWS Shield Response Team (SRT) can be engaged for expert assistance
- Cost protection prevents unexpected scaling charges caused by attack traffic
- Integration with AWS WAF allows blocking suspicious IPs, countries, or request patterns at Layer 7
Outcome
- Website remains available during the attack.
- Legitimate customers continue shopping without interruption.
- Backend infrastructure is protected from overload.
- No manual intervention is required.
- Business impact is minimized.