5.1.3. VPC Flow Logs for Network Traffic Analysis
First Principle: VPC Flow Logs capture detailed IP traffic information for network interfaces in your Amazon VPC, providing essential visibility for network security analysis, threat detection, and troubleshooting.
VPC Flow Logs are a powerful feature that enables security specialists to monitor the IP traffic going to and from network interfaces in their Amazon VPC. They are crucial for network diagnostics, security incident response, and compliance auditing.
Key Features of VPC Flow Logs:
- Traffic Capture: Records information about IP traffic, including source/destination IP address, port, protocol, packets, bytes, and action (ACCEPT or REJECT). This provides a detailed record of every network "flow."
- Scope: Can be enabled for an entire VPC, a subnet, or a specific Elastic Network Interface (ENI) (attached to EC2 instances, load balancers, NAT Gateways, etc.).
- Destinations: Flow log records can be published to Amazon CloudWatch Logs or Amazon S3 for storage and analysis.
- Use Cases:
- Security Analysis: Identifying unusual traffic patterns (e.g., traffic from known malicious IP addresses), unauthorized access attempts, data exfiltration attempts, or potential DDoS attacks.
- Network Diagnostics: Debugging connectivity issues between EC2 instances or to external networks.
- Compliance Auditing: Providing an audit trail of network traffic for regulatory compliance.
- Integrated with Amazon GuardDuty: GuardDuty analyzes VPC Flow Logs to detect threats.
Scenario: You need to monitor all IP traffic going to and from your production VPC for security purposes. This includes detecting suspicious outbound connections from compromised EC2 instances or unauthorized inbound traffic.
Reflection Question: How do VPC Flow Logs, by capturing detailed IP traffic information for network interfaces and publishing it to CloudWatch Logs or S3, fundamentally provide essential visibility for network security analysis, enabling proactive threat detection and efficient troubleshooting?