Community Id Spec

Abstract

1. Introduction

When processing flow data from a variety of monitoring applications (such as Zeek and Suricata), it's often desirable to pivot quickly from one dataset to another. While the required flow tuple information is usually present in the datasets, the details of such "joins" can be tedious, particular in corner cases. This spec describes "Community ID" flow hashing, standardizing the production of a string identifier representing a given network flow, to reduce the pivot to a simple string comparison.

function community_id_v1(ipaddr saddr, ipaddr daddr, port sport, port dport, int proto, int seed=0) { # Get seed and all tuple parts into network byte order seed = pack_to_nbo(seed); # 2 bytes saddr = pack_to_nbo(saddr); # 4 or 16 bytes daddr = pack_to_nbo(daddr); # 4 or 16 bytes sport = pack_to_nbo(sport); # 2 bytes dport = pack_to_nbo(dport); # 2 bytes

function community_id_icmp(ipaddr saddr, ipaddr daddr, int type, int code, int seed=0) { port sport, dport;

2. Objective

An open standard for hashing network flows into identifiers, a.k.a "Community IDs".

This project demonstrates how Python can be applied to a real-world Cybersecurity & Ethical Hacking problem.

4. Technology Stack

5. System Requirements

General requirements for this technology stack — check the README for exact versions.

• Python 3.8 or later
• pip / virtualenv for dependencies
• VS Code, PyCharm or Jupyter Notebook
• Git (to clone the repository)

6. Installation & Setup

git clone https://github.com/corelight/community-id-spec.git
cd community-id-spec

Full setup instructions are in the project README.

7. Future Enhancements

Suggested extensions you can add to make this your own project.

• Add logging and alert notifications (email / Telegram)
• Write a threat model document for the tool
• Package it with Docker for safe lab testing

8. Viva / Review Questions

Common questions examiners ask for projects in this domain.

1. Which threat or attack does this project defend against?
2. What detection or protection technique is used and what are its limits?
3. How are false positives and false negatives handled?
4. Which cryptographic algorithms or security standards are involved?
5. What legal and ethical rules apply when testing a tool like this?

9. Source Code & License

This project is developed by corelight and published on GitHub under the BSD 3-Clause "New" or "Revised" License. Please follow the license terms and credit the original author when you use or modify this code.