Incident Response & Digital Forensics

Network Forensics

  • May 9, 2025
  • 0

Sherlocked Security – Network Forensics

Analyze, Investigate, and Respond to Network-Based Attacks – Deep Dive into Network Traffic and Communication Analysis for Cybersecurity Investigations

1. Statement of Work (SOW)

Service Name: Network Forensics
Client Type: Enterprises, SaaS Providers, Cloud-Native Platforms, Government Agencies
Service Model: On-Demand Engagement & Retainer Support
Compliance Alignment: NIST 800-53, ISO/IEC 27001, PCI-DSS, SOC 2, GDPR, HIPAA

Network Forensics Covers:

  • Packet Capture and Analysis (PCAP Files)
  • Intrusion Detection & Prevention System (IDS/IPS) Log Analysis
  • Network Traffic Anomaly Detection
  • Man-in-the-Middle (MitM) Attack Detection
  • Network Topology and Flow Analysis
  • Protocol Analysis (TCP/IP, HTTP, DNS, etc.)
  • Malware Communication & C2 Traffic Detection
  • Data Exfiltration and Breach Investigation
  • Network Incident Timeline Construction

2. Our Approach

[Preparation] → [Network Traffic Capture] → [Traffic Analysis & Anomaly Detection] → [Intrusion Detection Logs Review] → [Malware & C2 Traffic Detection] → [Incident Timeline Construction] → [Forensic Reporting] → [Remediation Guidance]

3. Methodology

  • Pre-Incident Setup: Ensure relevant network monitoring tools (IDS/IPS, firewalls, packet sniffers) are configured to capture critical data.
  • Traffic Capture: Collect network traffic using packet capture tools (Wireshark, tcpdump) to identify suspicious traffic patterns.
  • Network Traffic Analysis: Analyze captured traffic for anomalous activity, unusual protocols, and signs of data exfiltration.
  • Intrusion Detection Log Review: Investigate IDS/IPS logs to identify intrusions, misconfigurations, or signs of malware activity.
  • Malware & C2 Detection: Examine network traffic for evidence of Command and Control (C2) communication or malware exfiltrating data.
  • Timeline Construction: Build a timeline based on traffic logs, packet capture analysis, and system logs to piece together the sequence of events.
  • Forensic Reporting: Document findings, provide Indicators of Compromise (IOCs), and deliver a detailed analysis of the network intrusion.
  • Remediation Guidance: Advise on hardening network defenses, such as traffic filtering, patching vulnerabilities, and tightening firewall rules.

4. Deliverables to the Client

  1. Packet Capture (PCAP): A complete set of packet captures from the affected network segments during the attack.
  2. Forensic Network Traffic Analysis Report: A detailed report outlining the analysis of the network traffic, including findings, anomalies, and attack indicators.
  3. Indicators of Compromise (IOCs): Extracted IOCs such as IP addresses, URLs, file hashes, and other relevant data.
  4. Intrusion Timeline: A reconstructed timeline of the attack, showing the network traffic flow, compromised systems, and attack vectors.
  5. Malware and C2 Communication Evidence: Documentation of any evidence of malware communication, including IP addresses, domain names, and protocols used.
  6. Recommendations for Network Defense: Guidance on strengthening network security, including firewall rules, IDS/IPS configuration, and traffic monitoring enhancements.

5. What We Need from You (Client Requirements)

  • Network Traffic Logs: Access to network traffic logs, IDS/IPS logs, firewall logs, and other relevant network-related logs.
  • Network Topology: A map or diagram of the network topology, including segmented networks, subnets, and firewall configurations.
  • Packet Capture Permissions: Permission to capture and analyze network traffic from the affected or suspected network segments.
  • Incident Details: Information on the suspected attack, including any alerts, user reports, or system anomalies that led to the incident investigation.
  • Forensic Environment Setup: A dedicated environment for handling the network data, ensuring no interference with ongoing operations.

6. Tools & Technology Stack

  • Packet Capture:
    • Wireshark (packet capture and analysis)
    • tcpdump (command-line packet capture)
    • TShark (Wireshark’s command-line counterpart)
  • Network Traffic Analysis:
    • Suricata (open-source IDS/IPS)
    • Zeek (formerly known as Bro, network monitoring and traffic analysis)
    • NetFlow/SFlow (for flow-based traffic monitoring)
  • Malware Communication Detection:
    • Wireshark (to identify suspicious traffic patterns)
    • YARA (for detecting specific malware signatures in network traffic)
  • Log Analysis:
    • ELK Stack (Elasticsearch, Logstash, Kibana for centralized logging and analysis)
    • Splunk (for log aggregation and analysis)
    • MISP (Malware Information Sharing Platform)
  • Incident Timeline Tools:
    • TheHive (case management and analysis platform)
    • Moloch (large-scale packet capture and search)
    • Xplico (network forensics analysis tool)

7. Engagement Lifecycle

  1. Client Onboarding & Initial Incident Briefing
  2. Traffic Capture & Network Log Collection
  3. Network Traffic Analysis & Anomaly Detection
  4. Intrusion Detection Log Review
  5. Malware & C2 Communication Identification
  6. Attack Timeline Construction
  7. Forensic Reporting & Evidence Documentation
  8. Recommendations for Network Remediation
  9. Post-Incident Playbook Review & Network Defense Strategy Enhancement

8. Why Sherlocked Security?

Feature Sherlocked Advantage
Expert Traffic Analysis In-depth analysis of network traffic using packet capture and flow-based techniques.
IDS/IPS Expertise Advanced intrusion detection log analysis to spot suspicious activity early.
Real-Time Monitoring & Detection Proactive identification of network anomalies and attack indicators in real-time.
Malware C2 Detection Identify and analyze malware communications with external command and control servers.
Network Incident Timeline Construct a detailed timeline of events based on network traffic and logs.
Actionable Remediation Guidance Provide detailed recommendations to harden network defenses against future incidents.

9. Real-World Case Studies

DDoS Attack on E-Commerce Platform

Issue: Distributed Denial of Service (DDoS) attack impacted the availability of the platform.
Findings: Network traffic analysis revealed massive inbound traffic spikes, and IDS logs showed repeated requests to a specific application endpoint.
Outcome: The DDoS attack was mitigated by blocking IP ranges and rate-limiting traffic. An attack timeline was constructed, and evidence of the DDoS attack was documented. The platform implemented stronger DDoS protection measures moving forward.

Data Exfiltration in Healthcare Organization

Client: Healthcare provider experiencing unauthorized access to patient data.
Findings: Network forensics identified outgoing data streams, which were anomalous and targeted external servers. Packet captures showed encrypted traffic leaving the network without authorization.
Outcome: The exfiltration route was identified as an unpatched vulnerability in a legacy system. Immediate action was taken to patch the system, and data exfiltration was blocked.

10. SOP – Standard Operating Procedure

  1. Traffic Capture: Initiate packet capture for the affected network segments, using trusted tools like Wireshark or tcpdump.
  2. Network Log Collection: Gather IDS/IPS logs, firewall logs, and any other relevant network security logs.
  3. Traffic Analysis: Analyze network traffic for anomalies, unusual traffic spikes, or signs of exfiltration or malware communication.
  4. Malware & C2 Detection: Identify potential malware communication and C2 server interactions within the network traffic.
  5. Intrusion Timeline: Reconstruct the attack timeline using logs, packet capture data, and system alerts.
  6. Forensic Reporting: Create a detailed forensic report outlining the findings, attack vectors, IOCs, and timeline of events.
  7. Remediation Advice: Provide actionable recommendations for network defense improvement, such as traffic filtering, firewall tuning, and IDS/IPS configuration.

11. Network Forensics – Readiness Checklist

1. Pre-Incident Setup

  • [ ] Network Traffic Monitoring Tools: Ensure IDS/IPS, firewalls, and packet capture tools are configured to capture relevant traffic.
  • [ ] Network Topology Diagram: Provide a clear understanding of the network segments and security zones.
  • [ ] Log Collection Configuration: Ensure that network logs (IDS/IPS, firewall, flow data) are collected and stored for analysis.
  • [ ] Incident Response Plan: Ensure network forensics is part of the overall incident response plan.

2. During Network Forensics

  • [ ] Network Traffic Captured: Collect network traffic from the affected network segments or devices involved.
  • [ ] Log Analysis: Review IDS/IPS logs, firewall logs, and packet capture data for signs of malicious activity.
  • [ ] Anomaly Detection: Detect unusual traffic patterns, traffic spikes, or unexpected communication flows.
  • [ ] C2 Communication Identification: Identify any malicious command-and-control traffic or malware communication within the network.
  • [ ] Timeline Construction: Build a timeline of events based on captured network traffic and log data.

3. Post-Analysis Response

  • [ ] IOC Documentation: Generate IOCs based on network analysis, including IP addresses, URLs, and domain names.
  • [ ] Remediation Recommendations: Provide advice on strengthening network defenses, including updating IDS/IPS signatures and firewall rules.
  • [ ] Reporting: Deliver a comprehensive report detailing findings, IOCs, and actionable remediation steps.

4. Continuous Improvement

  • [ ] Incident Review: Conduct a review of the network forensic process and update the playbook based on lessons learned.
  • [ ] Monitoring Enhancements: Implement additional network traffic monitoring tools or improve existing ones.
  • [ ] Training & Awareness: Conduct regular network forensics training and drills to ensure rapid identification of network-based attacks.
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