Skills Development NetFlow Anomaly Detection

NetFlow Anomaly Detection

v20260317
analyzing-network-flow-data-with-netflow
Parses NetFlow v9/IPFIX data with Python's netflow library, builds traffic baselines, and applies statistical checks to flag volumetric spikes, port scans, data exfiltration, or C2 beaconing before producing a prioritized findings report.
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Overview

Instructions

  1. Install dependencies: pip install netflow
  2. Collect NetFlow/IPFIX data from routers or use the built-in collector: python -m netflow.collector -p 9995
  3. Parse captured flow data using netflow.parse_packet().
  4. Analyze flows for:
    • Port scanning: single source to many destinations on same port
    • Data exfiltration: high byte-count outbound flows to unusual destinations
    • C2 beaconing: periodic connections with consistent intervals
    • Volumetric anomalies: traffic spikes beyond baseline thresholds
  5. Generate a prioritized findings report.
python scripts/agent.py --flow-file captured_flows.json --output netflow_report.json

Examples

Parse NetFlow v9 Packet

import netflow
data, _ = netflow.parse_packet(raw_bytes, templates={})
for flow in data.flows:
    print(flow.IPV4_SRC_ADDR, flow.IPV4_DST_ADDR, flow.IN_BYTES)
Info
Category Development
Name analyzing-network-flow-data-with-netflow
Version v20260317
Size 8.4KB
Updated At 2026-03-18
Language