Technical field guide
The sections below preserve the service-specific depth behind Network Forensics, edited for the current national practice and its documented engagement model. Methods are selected for the source, authorization, system state and assigned specialty. No single tool or artifact establishes a conclusion, and legal, regulatory or certification decisions remain with the responsible authority.
What Network Forensics Covers
Network forensics encompasses the collection and forensic examination of all data artifacts that document the behavior of networked systems: the traffic they exchange, the connections they establish, the protocols they use, and the anomalies that indicate unauthorized activity. Unlike host-based forensics, which examines the artifacts left on individual computers or servers, network forensics captures evidence of communications as they traverse the network infrastructure itself. This makes network forensics essential in matters where the host-based artifacts have been destroyed, altered, or are otherwise unavailable, and in cases where the forensic question concerns communications between parties rather than activity on a single device.
A network examination can draw from the available traffic, flow, infrastructure and authentication records:
- Packet capture analysis: examination of full-content packet captures (PCAPs) in Wireshark and specialized forensic tools to reconstruct sessions, extract transferred files, recover transmitted credentials, and document communications at the protocol level
- Protocol analysis: forensic examination of TCP/IP, DNS, HTTP and HTTPS, SMTP and IMAP, FTP, SSH, RDP, SMB, LDAP, Kerberos, and custom application protocols to document what was communicated and how
- Firewall and proxy log analysis: examination of firewall connection logs, proxy access logs, and URL filtering records to reconstruct network activity, identify policy violations, and document data exfiltration paths
- IDS/IPS alert correlation: analysis of intrusion detection and prevention system alerts to identify attacker activity, correlate alerts across time and infrastructure, and reconstruct attack sequences
- NetFlow and sFlow analysis: examination of flow records to document traffic volumes, connection patterns, and data transfer quantities even where full packet capture is not available
- DNS log analysis: DNS query and response logs examined to identify command-and-control communications, data exfiltration via DNS tunneling, domain generation algorithm (DGA) activity, and DNS reconnaissance
- Wireless network forensics: analysis of wireless access point logs, 802.11 frame captures, and wireless management system records to document unauthorized wireless access or device activity
- VPN traffic and authentication log analysis: VPN connection records, authentication logs, and session metadata examined to document authorized and unauthorized remote access
- Encrypted traffic metadata analysis: where content decryption is not available, analysis of connection metadata, certificate information, timing, and behavioral patterns to characterize encrypted communications
- Session reconstruction and timeline building: assembly of evidence from multiple network sources into a coherent chronological narrative of network events
Network forensics evidence is particularly powerful in matters where the opposing party claims that specific communications did not occur, that data was not exfiltrated, or that a breach was limited in scope. Preserved network records can corroborate communications independently of a single endpoint, but their weight depends on sensor placement, retention, clock alignment, encryption and logging coverage.
GDF's Network Forensics Process
A network-forensics engagement should preserve the available sources, document analytical choices and distinguish observed traffic from inference. The engagement begins with evidence identification and collection, conducted with the care required to establish and maintain documented chain of custody. Network evidence sources are diverse and often volatile: packet captures and infrastructure logs may rotate quickly or be overwritten without notice. Immediate triage prioritizes volatile records according to their retention window and relevance.
Evidence collection covers all available sources: router and firewall logs exported directly from the device or management system, packet capture files from network taps or analysis appliances, SIEM log exports, proxy logs, VPN server logs, wireless infrastructure logs, and NetFlow data from network device exporters. For each source, the collection record should identify date and time, operator, method, scope, available integrity values and each custody transfer. This documentation is essential when the evidentiary value of network records is challenged in litigation.
The analysis phase employs a combination of specialist tooling and manual analyst examination. Tooling may include protocol analyzers, network-artifact extractors, structured traffic analyzers, detection engines and purpose-built correlation scripts. Tool choice and version belong in the case record. Analyst-driven timeline reconstruction assembles findings from all sources into a chronological record of events, identifying the sequence of attacker actions, the systems affected, and the data accessed or transmitted.
GDF's network forensics reports are structured in two layers. The technical report presents each reported finding with the supporting evidence, specific timestamps, source and destination IP addresses (with attribution where determinable), byte volumes, protocol-level detail, and analyst methodology notes sufficient to allow an opposing expert to reproduce the analysis. The attorney-facing sections translate these findings into plain-language narrative, identifying key events, their relevance to the stated questions and the limitations of the available evidence. When expert support is in scope, the examiner can explain the reported protocol behavior, methods and limitations in deposition or testimony.