Network forensics is the capture, recording, and analysis of network traffic to investigate security incidents, reconstruct attack timelines, identify compromise indicators, and gather evidence for legal proceedings. It combines packet-level analysis with flow data examination to build a comprehensive picture of network activity during and around security events.
Network forensics employs two primary data sources. Full packet capture stores complete packet contents, enabling payload reconstruction, credential extraction, and file carving from network streams. Flow data (NetFlow, sFlow, IPFIX) provides metadata about connections including source, destination, ports, bytes transferred, and timing without storing payload content. Forensic analysis begins with timeline reconstruction, identifying the scope and sequence of events. Protocol analysis decodes communications to identify command-and-control traffic, data exfiltration, and lateral movement. Statistical analysis reveals anomalies in traffic volume, connection patterns, and protocol usage. DNS forensics examines query logs for indicators of domain generation algorithms, DNS tunneling, and C2 beaconing. Analysts use tools including Wireshark, NetworkMiner, Zeek, and Moloch/Arkime for packet analysis, and SiLK and nfdump for flow analysis. Evidence handling follows chain-of-custody procedures to maintain admissibility, including hash verification of capture files and secure storage.
Network traffic provides an objective record of communications that attackers cannot easily erase, unlike endpoint logs that can be deleted or manipulated. Forensic analysis of network data often reveals the full scope of an incident, including compromised systems, data exfiltration volume, and attacker infrastructure. It identifies initial access vectors and lateral movement paths that inform remediation. In legal and regulatory contexts, network forensic evidence supports breach notification decisions, litigation, and law enforcement investigations.
CDA positions network forensics within the Threat Intelligence and Defense domain. Our missions build forensic readiness through capture infrastructure deployment, retention policy design, analyst training, and incident response integration. We conduct forensic exercises that validate the organization's ability to reconstruct network events during investigations.