performing-network-packet-capture-analysis

# Performing Network Packet Capture Analysis ## Overview Network packet captures (PCAP/PCAPNG files) represent the ultimate source of truth about network activity and provide irrefutable evidence of communications between hosts. PCAP files log every packet transmitted over a network segment, making them vital for forensic investigations involving data exfiltration, command-and-control communications, lateral movement, malware delivery, and unauthorized access. Wireshark is the primary tool for interactive analysis, while tshark provides command-line capabilities for automated processing and scripting. Modern PCAPNG format supports additional metadata including interface descriptions, capture comments, precise timestamps, and per-packet annotations. ## When to Use - When conducting security assessments that involve performing network packet capture analysis - When following incident response procedures for related security events - When performing scheduled security testing or auditing activities - When validating security controls through hands-on testing ## Prerequisites - Wireshark 4.x with protocol dissectors - tshark command-line tool (included with Wireshark) - tcpdump for capture and basic filtering - Python 3.8+ with scapy and pyshark libraries - Sufficient disk space for PCAP files (can be multi-GB) ## Capture Techniques ### tcpdump ```bash # Capture all traffic on interface eth0 tcpdump -i eth0 -w capture.pcap # Capture with rotation (100MB files, keep 10)...