net-traffic-wrshrk

name	net-traffic-wrshrk
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.

Prerequisites

• Wireshark 4.0+ and tshark command-line utility installed
• Root/sudo privileges or membership in the wireshark group for live packet capture
• Network interface access (physical NIC, span port, or network tap) to the monitored segment
• Sufficient disk space for packet capture files (estimate 1 GB per minute on busy gigabit links)
• Familiarity with TCP/IP protocols, HTTP, DNS, TLS, and SMB at the packet level

Workflow

Step 1: Configure Capture Environment

Set up the capture interface and filters to target relevant traffic:

# List available interfaces
tshark -D

# Start capture on eth0 with a capture filter to limit scope
tshark -i eth0 -f "host 10.10.5.23 and (port 80 or port 443 or port 445)" -w /tmp/capture.pcapng

# Capture with ring buffer to manage disk usage (10 files, 100MB each)
tshark -i eth0 -b filesize:102400 -b files:10 -w /tmp/rolling_capture.pcapng

# Capture on multiple interfaces simultaneously
tshark -i eth0 -i eth1 -w /tmp/multi_interface.pcapng

For Wireshark GUI, set capture filter in the Capture Options dialog before starting.

Step 2: Apply Display Filters for Targeted Analysis

# Filter HTTP traffic containing suspicious user agents
tshark -r capture.pcapng -Y "http.user_agent contains \"curl\" or http.user_agent contains \"Wget\""

# Find DNS queries to suspicious TLDs
tshark -r capture.pcapng -Y "dns.qry.name contains \".xyz\" or dns.qry.name contains \".top\" or dns.qry.name contains \".tk\""


tshark -r capture.pcapng -Y 


tshark -r capture.pcapng -Y  -T fields -e ip.src -e ip.dst -e smb2.filename


tshark -r capture.pcapng -Y 


tshark -r capture.pcapng -Y  -T fields -e frame.time_relative -e ip.src -e tcp.dstport