byob for studying post-exploitation framework architecture in the lab

byob is an open-source post-exploitation framework built in Python for students, researchers and developers who need to study C2 architecture, payload generation and defensive detection techniques inside authorized lab environments.

Tool	malwaredllc/byob — open-source post-exploitation framework with a C2 server, payload generator and remotely importable modules
Category	Post-exploitation / command-and-control framework (educational)
Primary Use	Learning how C2 servers, reverse TCP shells, staged payloads and remote module imports work, in lab and research settings
Safe Use	The project's own disclaimer restricts it to authorized testing or educational purposes; use only on systems you own, in isolated lab networks, or during contractually authorized assessments
Telemetry Note	Clients beacon out via reverse TCP to the server with AES-256 encrypted traffic; defenders can observe the outbound connection patterns, SQLite session persistence artifacts on the operator side, and sandbox/AV-evasion behaviors as detection research subjects

byob (Build Your Own Botnet) is one of the most starred educational security projects on GitHub, sitting at roughly 9.5k stars under the malwaredllc organization, licensed GPL-3.0 and written almost entirely in Python. The README is explicit about intent: this is a post-exploitation framework for students, researchers and developers, and it carries a disclaimer that it should be used for authorized testing or educational purposes only. What makes it interesting from a documentary standpoint is not raw capability but architecture — it is essentially a teaching scaffold that lets you dissect how a modern C2 framework is assembled without writing one from scratch.

The project is split into two main deliverables: the original console-based application under /byob and a web GUI under /web-gui. The console version is the pedagogical core, exposing the moving parts directly. The web GUI adds a dashboard with a point-and-click interface for executing post-exploitation modules, an interactive map of client machines, and an in-browser terminal emulator so the operator retains direct shell access even from the browser. Version 2.0, per the badge in the README, is the current release, with an active Discord support server and wiki documentation.

The most technically distinctive idea in byob is remote imports, implemented in byob.core.loaders. Instead of bundling functionality into the payload, a client can remotely import third-party packages and modules from the server at runtime, without writing them to disk or installing anything locally. The README claims zero disk IO from this path — arbitrary code is loaded into memory and imported directly into the running process. This is the mechanism that keeps the generated client small while allowing unlimited modules, since features live server-side and are streamed in on demand.

The client design philosophy reads like a checklist of evasion research topics. The README enumerates: no dependencies (not even Python itself, since clients can be compiled into portable binaries for Windows or standalone apps for macOS), encrypted payloads using a random 256-bit key held only in the generated stager, abort-on-sandbox-or-VM detection, and blocking of processes named after known antivirus products. Each of these is a well-known adversary technique, and for defenders the README is effectively a free curriculum on what fileless, staged malware families try to do.

Network behavior is equally instructive. Clients connect back to the server via reverse TCP connections, which the README notes will bypass most default firewall configurations because firewalls primarily filter inbound connections. Session traffic is encrypted with AES-256 after key agreement via Diffie-Hellman IKE (RFC 2409). The byob.core.security module actually offers three modes — AES-256-OCB, AES-256-CBC and XOR-128 — which is a useful spread for anyone studying how crypto choices affect observability and confidentiality in C2 channels.

The payload generator in the web GUI has a genuinely unusual implementation detail: it uses Docker containers and Wine servers to cross-compile executables for arbitrary platform and architecture combinations from a single host. From an engineering perspective this is the most creative part of the codebase, and worth reading even if you never generate anything — it is a practical example of hermetic cross-compilation infrastructure wrapped behind a web form.

Module extensibility is where byob earns its "for developers" framing. Any Python script, module or package dropped into ./byob/modules/ automatically becomes remotely importable by every connected client while the server is running, and a module template is provided to lower the barrier further. Clients periodically poll the server and dynamically update their in-memory resources when content is added or removed. The stock module set includes persistence (five methods), packetsniffer (uploads a .pcap), escalate (UAC bypass), portscanner, keylogger, screenshot, outlook, process control and an icloud check on macOS — twelve post-exploitation modules in total per the README.

On the server side, byob/server.py implements a console UI driving reverse TCP shells, backed by a persistent SQLite database via byob.core.dao. That persistence layer is a design choice worth noting: it stores identifying information about client hosts so sessions survive disconnections of arbitrary duration, which the README frames as enabling long-term reconnaissance. The byob.core.handler module provides an HTTP POST handler for remote file uploads, rounding out the core library alongside util, payloads, stagers and generators.

For blue teams, byob has real value as a detection research target. Because the crypto, staging and import mechanics are all documented and open source, you can stand up an isolated lab pair — server and victim VM — and instrument the network path to study what reverse TCP beacons with AES-256 payloads look like on the wire, or how the periodic server-polling behavior manifests as periodicity in egress traffic. None of the evasion claims should be taken at face value either; testing them against a modern EDR stack in a lab is itself a legitimate exercise.

The roadmap section is candid about current limitations, which is refreshing. Remote import encryption is listed as unfinished — the data streams of remotely imported packages are not yet encrypted, and the authors explicitly flag the deserialization risk of remote code execution that this introduces. Additional transports (HTTP/S, DNS) are also still to-do. Anyone evaluating this framework for research should read those caveats carefully, because the remote import channel is the architectural heart of the tool and it is currently the least hardened component.

Installation is standard for a Python project: clone the repository from github.com/malwaredllc/byob and follow the wiki setup, which covers the console app and the web-gui separately. The Docker-based compilation path in the GUI presupposes container infrastructure on the operator host. Given the GPL license and the active Discord community, contributions are explicitly welcomed via pull requests.

The bottom line for an authorized professional: byob is best treated as a readable, modular reference implementation of post-exploitation architecture — remote imports, staged payloads, encrypted C2, session persistence — rather than as operational tooling. Its README, code layout (core, modules, payloads, server.py) and honest to-do list make it a solid companion for coursework, CTF infrastructure study, and detection engineering experiments run entirely inside environments you control.

Official project repository for malwaredllc/byob.

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Educational analysis for authorized security professionals. Use only in controlled, authorized environments.