Understanding DDoS Attacks#
Distributed Denial of Service (DDoS) can cripple your online services within minutes—understanding attack types and having prepared responses is critical for business continuity.
This guide covers DDoS fundamentals: attack types, detection methods, mitigation strategies, response playbooks, and architectural hardening to improve resilience.
Attack Detection#
Early detection enables faster response. Establish baselines and monitor for anomalies that indicate DDoS activity.
Baseline Establishment
Document normal traffic patterns: bandwidth usage, request rates, geographic distribution, protocol mix. Baselines enable anomaly detection. Update baselines for seasonal variations.
Real-Time Monitoring
Monitor traffic continuously: inbound bandwidth, packets per second, connection rates, error rates. Use network monitoring tools and SIEM for correlation.
Anomaly Detection
Configure alerts for baseline deviations: sudden traffic spikes, unusual protocols, geographic anomalies, connection exhaustion. Balance sensitivity to minimize false positives.
Attack Classification
When attack detected: identify attack type (volumetric, protocol, application), source distribution, target resources. Classification guides mitigation strategy selection.
False Positive Management
Mitigation Strategies#
Effective DDoS mitigation requires layered defenses. No single solution handles all attack types and volumes.
On-Premise Defenses:
- Rate limiting at firewall and load balancer
- SYN cookies for SYN flood protection
- Connection limits per source IP
- Blackholing obvious attack sources
Layered Defense
Response Playbook#
When attacks occur, follow prepared response procedures. Document playbooks before incidents to ensure consistent, rapid response.
Detection and Triage
Confirm attack in progress. Classify attack type and severity. Notify incident response team. Begin logging attack characteristics. Initial assessment within 5 minutes.
Escalation
Notify stakeholders based on severity. Engage DDoS mitigation provider if using scrubbing service. Alert ISP for large volumetric attacks. Activate crisis communication plan.
Mitigation Activation
Implement mitigation based on attack type. Activate CDN protections. Enable rate limiting. Divert traffic to scrubbing if needed. Monitor effectiveness and adjust.
Communication
Update status page for external communication. Notify affected customers. Internal updates to leadership. Document timeline for post-incident review.
Recovery and Review
Confirm attack has subsided. Gradually restore normal operations. Remove temporary mitigations carefully. Conduct post-incident review within 72 hours.
Key Contacts to Pre-Establish:
- DDoS mitigation provider emergency line
- ISP/hosting provider NOC contacts
- CDN provider support escalation
- Internal incident response team
Communication Timing
Architectural Prevention#
Design infrastructure to withstand attacks. Architectural hardening reduces attack impact and improves recovery speed.
Capacity Planning
Provision excess capacity for traffic spikes. Plan for 3-5x normal peak traffic. Include burst capacity in cloud contracts. Test capacity limits before attacks reveal them.
Network Hardening
Implement ingress filtering (BCP38). Configure TCP stack for resilience. Tune connection timeouts. Block unnecessary protocols. Implement rate limiting at network edge.
Application Hardening
Optimize application for high request rates. Implement caching aggressively. Use connection pooling. Design APIs to handle graceful degradation under load.
Testing and Validation
Conduct regular DDoS simulations. Test mitigation activation procedures. Validate failover mechanisms. Document lessons learned and update architecture.
Origin Protection
References and Resources#
Additional resources for DDoS mitigation planning and implementation.
Cloud Provider Documentation:
- AWS Shield Developer Guide
- Azure DDoS Protection Standard Documentation
- Google Cloud Armor Documentation
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