SEC05: How do you protect your network resources?
Any workload that has some form of network connectivity, whether it's the internet or a private network, requires multiple layers of defense to help protect from external and internal network-based threats. All network traffic that flows to and from your workload should be controlled at multiple layers with a combination of controls. These controls should include network access controls, such as subnets or security groups, as well as application-level controls, such as web application firewalls.
Best Practices
This question includes the following best practices:
Key Concepts
Network Security Fundamentals
Defense in Depth: Implement multiple layers of network security controls to protect against various types of threats. No single control should be relied upon to secure your entire network infrastructure.
Network Segmentation: Divide your network into smaller, isolated segments to limit the blast radius of security incidents and control traffic flow between different parts of your workload.
Zero Trust Networking: Verify and authenticate all network traffic, regardless of its source or destination. Never trust traffic based solely on network location.
Least Privilege Network Access: Grant only the minimum network access required for legitimate business functions, applying the principle of least privilege to network connectivity.
Network Protection Layers
Perimeter Security: Protect the boundary between your network and external networks (internet, partner networks) using firewalls, intrusion detection systems, and DDoS protection.
Internal Network Security: Secure traffic flow within your network using micro-segmentation, internal firewalls, and network access controls.
Application Layer Security: Protect applications from network-based attacks using web application firewalls, API gateways, and application-specific security controls.
Infrastructure Security: Secure the underlying network infrastructure including routers, switches, load balancers, and network management systems.
AWS Services to Consider
Implementation Approach
1. Network Architecture Design
- Design VPC architecture with proper segmentation
- Plan subnet structure for different tiers (public, private, database)
- Implement network isolation between environments
- Design connectivity patterns for hybrid and multi-cloud scenarios
- Plan for scalability and future growth
2. Access Control Implementation
- Configure security groups with least privilege rules
- Implement Network ACLs for additional subnet-level protection
- Set up VPC endpoints for secure service access
- Configure NAT gateways for outbound internet access
- Implement private connectivity using AWS PrivateLink
3. Traffic Inspection and Protection
- Deploy AWS WAF for application-layer protection
- Implement AWS Network Firewall for advanced inspection
- Configure intrusion detection and prevention systems
- Set up network monitoring and logging
- Implement threat intelligence integration
4. DDoS Protection and Resilience
- Enable AWS Shield Standard (automatic)
- Consider AWS Shield Advanced for enhanced protection
- Implement CloudFront for content delivery and protection
- Configure auto-scaling for traffic spikes
- Set up monitoring and alerting for DDoS events
Network Security Architecture
Multi-Tier Network Architecture
Defense in Depth Implementation
Traffic Flow Control
Network Security Controls Framework
Preventive Controls
- Network Segmentation: VPC design, subnets, security groups
- Access Controls: Security group rules, NACLs, VPC endpoints
- Traffic Filtering: Firewalls, WAF rules, content filtering
- Encryption: TLS/SSL, VPN connections, encrypted protocols
Detective Controls
- Traffic Monitoring: VPC Flow Logs, network monitoring tools
- Intrusion Detection: Network-based IDS, anomaly detection
- Log Analysis: CloudTrail, DNS logs, firewall logs
- Threat Intelligence: IP reputation, domain analysis
Responsive Controls
- Automated Blocking: WAF rules, security group updates
- Traffic Redirection: Route table updates, load balancer changes
- Incident Isolation: Network segmentation, access revocation
- DDoS Mitigation: Shield response, traffic shaping
Common Challenges and Solutions
Challenge: Complex Network Architectures
Solution: Use infrastructure as code (CloudFormation/CDK) to standardize network deployments, implement consistent naming conventions, and document network designs thoroughly.
Challenge: Managing Security Group Rules at Scale
Solution: Implement centralized security group management, use automation for rule updates, and establish approval processes for security group changes.
Challenge: East-West Traffic Security
Solution: Implement micro-segmentation using security groups, deploy internal firewalls, and use VPC endpoints to reduce internet-bound traffic.
Challenge: DDoS Attack Mitigation
Solution: Enable AWS Shield Advanced, implement CloudFront for content delivery, configure auto-scaling, and establish DDoS response procedures.
Challenge: Network Performance vs Security
Solution: Optimize security controls for performance, use managed services to reduce overhead, and implement intelligent traffic routing.
Network Security Maturity Levels
Level 1: Basic Network Security
- Basic VPC setup with public and private subnets
- Security groups with broad rules
- Manual network configuration and management
- Limited network monitoring and logging
Level 2: Structured Network Security
- Well-designed multi-tier network architecture
- Properly configured security groups and NACLs
- VPC Flow Logs enabled for monitoring
- Basic WAF implementation for web applications
Level 3: Advanced Network Security
- Comprehensive network segmentation and micro-segmentation
- Advanced threat detection and automated response
- Network Firewall deployment with custom rules
- Integrated DDoS protection and monitoring
Level 4: Optimized Network Security
- AI/ML-powered threat detection and response
- Automated network security orchestration
- Advanced analytics and threat intelligence integration
- Continuous optimization based on traffic patterns
Network Protection Best Practices
Network Design:
- Implement Network Segmentation: Separate different tiers and environments
- Use Multiple Availability Zones: Distribute resources for resilience
- Plan IP Address Space: Use RFC 1918 private address ranges efficiently
- Design for Scalability: Plan for future growth and expansion
- Document Network Architecture: Maintain current network diagrams and documentation
Access Control:
- Apply Least Privilege: Grant minimum required network access
- Use Security Groups Effectively: Implement specific, purpose-built rules
- Layer Network Controls: Combine security groups, NACLs, and firewalls
- Regular Rule Review: Audit and clean up unnecessary rules
- Automate Rule Management: Use infrastructure as code for consistency
Traffic Protection:
- Enable Comprehensive Logging: VPC Flow Logs, DNS logs, firewall logs
- Implement WAF Protection: Protect web applications from common attacks
- Use Managed Services: Leverage AWS managed security services
- Monitor Traffic Patterns: Establish baselines and detect anomalies
- Integrate Threat Intelligence: Use external feeds for enhanced protection
Key Performance Indicators (KPIs)
Security Metrics:
- Number of blocked attacks and threats
- Security rule coverage and effectiveness
- Mean time to detect network threats (MTTD)
- False positive rate for security alerts
Performance Metrics:
- Network latency and throughput
- Security control processing overhead
- Availability and uptime metrics
- User experience impact measurements
Operational Metrics:
- Security group rule compliance rate
- Network configuration drift detection
- Automated response success rate
- Security incident resolution time