Wireshark in Security Analysis and Incident Response

Introduction

Wireshark is not just a network troubleshooting tool; it's also a powerful ally in cybersecurity.
This guide will explore how to use Wireshark effectively for security analysis and incident response.

Pro Tip: Always ensure you have proper authorization before capturing and analyzing network traffic, especially in security contexts.

Setting Up Wireshark for Security Analysis

Update Wireshark: Ensure you're using the latest version to have access to the most recent security-related dissectors and features.
Configure Promiscuous Mode: Enable this to capture all traffic on the network segment, not just traffic destined for your machine.
Set Up Decryption: Configure SSL/TLS decryption if you have the necessary keys (Edit > Preferences > Protocols > TLS).
Create Security Profiles: Set up custom profiles with security-focused column layouts and color rules (Edit > Configuration Profiles).

Key Security Analysis Techniques

1. Identifying Suspicious Traffic Patterns

Look for unusual port numbers or protocol anomalies
Monitor for high volumes of traffic to/from unexpected hosts
Check for patterns indicative of scanning or brute force attempts

2. Analyzing Payload Content

Inspect HTTP/HTTPS traffic for potential web-based attacks
Look for unusual strings or encoded data in packet payloads
Use the "Follow TCP Stream" feature to reconstruct and analyze full conversations

3. Detecting Command and Control (C2) Traffic

Look for periodic beaconing to suspicious IP addresses
Analyze DNS queries for potential domain generation algorithms (DGAs)
Inspect encrypted traffic patterns for signs of C2 communication

4. Identifying Data Exfiltration

Monitor for large data transfers to external IP addresses
Look for sensitive data patterns in outgoing traffic
Analyze protocols typically used for file transfers (FTP, SFTP, HTTP POST)

Useful Wireshark Filters for Security Analysis

Filter	Purpose
`http.request.method == "POST"`	Identify potential data uploads or form submissions
`dns.qry.name contains "example"`	Look for specific domain queries, useful for detecting C2
`ip.addr == 10.0.0.1 && tcp.port == 4444`	Focus on traffic to/from a specific IP and port
`tls.handshake.type == 1 && tls.handshake.ciphersuite == 0x0088`	Detect potential SSL/TLS downgrade attacks
`http.user_agent contains "nmap"`	Identify potential network scanning activities

Incident Response with Wireshark

Capture Relevant Traffic: Start capturing as soon as an incident is suspected.
Isolate Affected Systems: Use display filters to focus on traffic to/from compromised hosts.
Timeline Analysis: Use the "Time" column to understand the sequence of events.
Identify IOCs: Extract potential Indicators of Compromise (IOCs) like IP addresses, domains, and file hashes.
Data Reconstruction: Use file extraction features to recover transferred files if necessary.
Document Findings: Use Wireshark's reporting features to document your analysis.

Warning: Be cautious when analyzing potentially malicious traffic. Always conduct analysis in a secure, isolated environment.

Advanced Security Analysis Features

Expert Information: Use Wireshark's built-in expert system to highlight potential security issues (Analyze > Expert Information).
Protocol Hierarchy Statistics: Quickly identify unusual protocols in your capture (Statistics > Protocol Hierarchy).
Conversations: Analyze communication patterns between hosts (Statistics > Conversations).
Flow Graphs: Visualize the sequence of packets in a potential attack (Statistics > Flow Graph).
Lua Scripting: Develop custom dissectors or analysis scripts for specific threats or protocols.

Integration with Other Security Tools

Wireshark can be used in conjunction with other security tools to enhance analysis:

Use Snort or Suricata rules to identify known threats in Wireshark captures.
Export data to ELK Stack for long-term storage and advanced analytics.
Combine Wireshark analysis with log data from SIEM systems for comprehensive incident investigation.

Best Practices for Security Analysis with Wireshark

Regularly update your Wireshark installation and dissectors.
Maintain a library of known-good traffic samples for comparison.
Use capture filters judiciously to avoid overwhelming your system during long-term monitoring.
Collaborate with other analysts and share findings to improve threat detection capabilities.
Stay informed about the latest threats and how they manifest in network traffic.
Practice ethical considerations and respect privacy laws when capturing and analyzing traffic.