analyzing-network-traffic-with-wireshark

name	analyzing-network-traffic-with-wireshark
description	Captures and analyzes network packet data using Wireshark and tshark to identify malicious traffic patterns, diagnose protocol issues, extract artifacts, and support incident response investigations on authorized network segments.
domain	cybersecurity
subdomain	network-security
tags	["network-security","wireshark","packet-analysis","traffic-analysis","pcap"]
version	1.0
author	mahipal
license	Apache-2.0
nist_csf	["PR.IR-01","DE.CM-01","ID.AM-03","PR.DS-02"]

Analyzing Network Traffic with Wireshark

When to Use

• Investigating suspected network intrusions by examining packet-level evidence of command-and-control traffic, data exfiltration, or lateral movement
• Diagnosing network performance issues such as retransmissions, fragmentation, or DNS resolution failures
• Analyzing malware communication patterns by capturing traffic from sandboxed or isolated hosts
• Validating firewall and IDS rules by confirming what traffic is actually traversing network segments
• Extracting files, credentials, or indicators of compromise from captured network sessions

Do not use to capture traffic on networks without authorization, to intercept private communications without legal authority, or as a substitute for full-featured SIEM platforms in production monitoring.

Detection Gaps & Validation

• You only see what the tap delivers: a SPAN port that mirrors one direction, or oversubscription dropping frames, makes beaconing look intermittent. Confirm with tshark -r cap.pcapng -q -z io,phs and check the capture's dropped-packet count before concluding traffic is absent.
• Encrypted exfil/C2 hides from display filters: DoH/DoT (tcp.port==443/853) carries no dns.qry.name to grep — your .xyz TLD filter returns nothing. Pivot to tls.handshake.extensions_server_name (SNI), JA3/JA3S, and tcp.len periodicity instead of assuming the host is clean.
• Display filter != capture filter: a capture BPF of port 53 permanently discards the DoH/DoT and non-53 tunnels you later want; capture broad, filter narrow at analysis time.
• Low-and-slow beats the eye: beacons with jitter won't stand out in a packet list. Use -z io,stat,1 and -z conv,tcp sorted by duration to surface long, low-byte conversations to one destination.
• Validate your filter fires: replay a known-bad sample with tcpreplay -i eth0 known_c2.pcap (or open it directly) and confirm your display filter (e.g., dns.qry.name matches "[a-f0-9]{30,}") actually matches the malicious frames; a zero-row result means the field path or operator is wrong.
• FP tuning: TLS SNI to CDNs, Windows update, and corporate DoH resolvers trigger naive TLD/long-label filters; baseline and whitelist before alerting.

Prerequisites

• Wireshark 4.0+ and tshark command-line utility installed