Network Archaeology

A combination of "Binary Network Protocols 101", "Cryptanalysis 101", and "Back Engineering 101", with a focus on mathematics and information theory.

The goal of this class is to learn how to write custom malware protocol decoder software. We do this by introducing several CS concepts: binary network protocols, elementary cryptanalysis, and back engineering (reverse engineering/cleanroom design. We also have an intense but occasional focus on mathematics and information theory.

People who are not deep into mathematics and computer science will still benefit from this class, but those who have a passion for theoretical CS, information theory, or mathematics, will gain the most.

The class is presented as a series of technical challenges, each teaching a concept by allowing students to invent different approaches and try them out, seeing which work well and which do not. Challenges build on each other, until, by the final challenge, students are writing custom binary protocol decoder software from scratch.

What to expect

Network Archaeology is a self-paced lab class, with intermittent instructor lectures. Some participants may find the first dozen or so labs easy: they are encouraged to proceed through as quickly as they like. The instructors lead occasional “how-to” lectures, starting with the first lab, eventually bringing the class to the same point. Between lectures, instructors traverse the room helping people with labs.

This class is taught using Linux. The instructor will exclusively use command-line tools, to create increasingly powerful tools, but participants can make decent progress using Wireshark (local install) and Cyber Chef (web-based tool).

Each lab exercise either introduces new concepts or builds on previously presented concepts. Very few people make it through every exercise, and there is no expectation that anyone will “finish” in two days. Many Network Archaeology attendees come back to Cyber Fire to take this class a second or even third time.

Day 1

  • Hexadecimal
  • Network Protocols (HTTP, SMTP, FTP, SSL, DNS)
  • Byte structure of TCP/IP
  • Encoding schemes (Hex, Base64)
  • Examining packet captures
  • Extracting transferred data from packet captures
  • Attack techniques against weak encryption
  • Helpful tools for Network Archaeology

Day 2

  • Entropy as it relates to cryptography
  • Application-layer protocol tunneling
  • Using sequencing meta-information to reconstruct transferred information
  • Analysis and decoding of novel binary protocols with no prior knowledge
  • Attacking novel compression with no prior knowledge
  • Attacking novel weak cryptography with no prior knowledge

Who should attend?

  • Computer scientists
  • Mathematicians
  • Information theorists
  • Incident investigators
  • Software engineers
  • Applied mathematicians
  • System administrators
  • Site reliability engineers

Is this the right class for me?

Network Archaeology teaches students how to approach unknown data that no existing tool can handle. People expecting to walk away with a recipe book will be disappointed. Our goal is for you to gain insight about how network protocols work, how encryption works, and what common techniques can be used to “break” malware protocols.

Network Archaeology is broadly interesting to anyone who wants a better understanding of the process of network packet forensic techniques. Even if you don’t intend to engage in this activity in your job, going through the instructor-led exercises will provide insight into challenges facing your organization.

Laptop Configuration

You will need a computer with a modern web browser, and a Linux command line. We recommend Ubuntu, either as your native OS, or in a virtual machine.

You should have the following packages pre-installed:

  • wireshark
  • tcpflow
  • tcpdump
  • python3
  • A C build toolchain:
    • apt install build-essential on Ubuntu / Debian / Mint
    • yum groupinstall 'Development Tools' on Red Hat / CentOS

We will not be able to help anyone configure their computer, so please arrive with a properly set up machine.

Other Operating Systems

If you really know what you’re doing, you can complete this class with MacOS or Windows. Be prepared to figure out your OS quirks on your own, however. Windows users should be prepared to write a lot of code, as our command-line recipes won’t work at all in Windows.