PcapXray - A Network Forensics Tool To visualize a Packet Capture offline as a Network Diagram

PcapXray is a Network Forensics Tool  To visualize a Packet Capture offline as a Network Diagram including device identification, highlight important communication and file extraction.

PcapXray Design Specification

Goal:
Given a Pcap File, plot a network diagram displaying hosts in the network, network traffic, highlight important traffic and Tor traffic as well as potential malicious traffic including data involved in the communication.

Problem:

• Investigation of a Pcap file takes a long time given initial glitch to start the investigation
  
• Faced by every forensics investigator and anyone who is analyzing the network
  
• Location: https://github.com/Srinivas11789/PcapXray
  

Solution: Speed up the investigation process

• Make a network diagram with the following features from a Pcap file Tool Highlights:
• Network Diagram – Summary Network Diagram of full network
• Information:
• Traffic with Server Details
• Tor Traffic
• Possible Malicious traffic
• Data Obtained from Packet in Report – Device/Traffic/Payloads
• Device Details

Tool Image:



Components:

• Network Diagram
• Device/Traffic Details and Analysis
• Malicious Traffic Identification
• Tor Traffic
• GUI – a gui with options to upload pcap file and display the network diagram

Python Libraries Used: - All these libraries are required for functionality

• Tkinter and TTK – Install from pip or apt-get – Ensure Tkinter and graphviz is installed (Most Linux contain by default)
  • apt install python-tk
  • apt install graphviz
• All these are included in the requirements.txt file
  • Scapy – rdpcap to read the packets from the pcap file
  • Ipwhois – to obtain whois information from ip
  • Netaddr – to check ip information type
  • Pillow – image processing library
  • Stem – tor consensus data fetch library
  • pyGraphviz – plot graph
  • Networkx – plot graph
  • Matplotlib – plot graph

Challenges:

• Unstability of the TK GUI:
  • Decision on the GUI between Django and TK, settled upon tk for a simple local interface, but the unstability of the tk gui caused a number of problems
• Graph Plotting:
  • Plotting a proper network graph which is readable from the data obtained was quite an effort, used different libraries to arrive at one.
• Performance and Timing:
  • The performance and timing of the total application was a big challenge with different data gathering and output generation

Known Bugs:

• Memory Hogging
  
  • Sometimes memory hogging occurs when lower RAM is present in the system as the data stored in the memory from the pcap file is huge
  • Should be Fixed by moving data into a database than the memory itself
• Race Condition
  
  • Due to mainloop of the TK gui, other threads could undergo a race condition
  • Should be fixed by moving to a better structured TK implementation or Web GUI
• Tk GUI Unstability:
  
  • Same reason as above
• Current Fix in rare occasions: If any of the above issue occurs the progress bar keeps running and no output is generated, a restart of the app would be required.
  

Future:

• Change the database from JSON to sqlite or prominent database, due to memory hogging
• Change fronend to web based such as Django
• Make the application more stable