WSC2: WebSocket C2 Tool

by do son · Published · Updated

WebSocket C2

WSC2 – A WebSocket C2 Tool

WSC2 is a PoC of using the WebSockets and a browser process to serve as a C2 communication channel between an agent, running on the target system, and a controller acting as the actual C2 server.

Architecture

WSC2 is composed of:

  • a controller, written in Python, which acts as the C2 server
  • an agent running on the target system delivered to the target system via various initial stagers
  • various flavors of initial stagers (created from the controller interface) used for the initial compromission of the target system

 

Features

WSC2 main features:

  • Various stager (powershell one-liner, various JScript file) – this is not limited, you can easily come up with your own stagers, check the templates folder to get an idea
  • Interactive shell (with environment persistency)
  • File transfer back and forth between the agent and C2
  • Multiple agents support

 

Installation & Configuration

Installation is pretty straightforward:

  • Git clone this repository: git clone https://github.com/Arno0x/WSC2 WSC2 && cd WSC2
  • Install the python dependencies: pip install -r requirements.txt
  • Give the execution rights to the main script: chmod +x wsc2.py

Check the configuration file config.py and ensure the default config fits your needs.

Start the controller by typing: ./wsc2.py.

Compiling your own agent

The JScript agent (stager ‘jscript1’) doesn’t need to be compiled.

The ‘jscript2’, ‘jscript3’ and ‘psoneliner’ stagers are based on a .Net assembly DLL that you can choose to build on your own/modify, based on the source code provided.

Although it is perfectly OK to use the provided wsc2.dll, you can very easily compile your own agent, from the source code provided. You’ll need Visual Studio installed.

Create a .Net (Visual C#) Class Libray project. Add the wsc2Agent.cs source file as the main source code file.

Add the following references to your project:

  • Microsoft HTML Object Library (MSHTML)
  • Microsoft Internet Controls (SHDocVw)

Build !

Tutorial

DISCLAIMER

This tool is intended to be used in a legal and legitimate way only:

either on your own systems as a means of learning, of demonstrating what can be done and how, or testing your defense and detection mechanisms
on systems, you’ve been officially and legitimately entitled to perform some security assessments (pentest, security audits)
Quoting Empire’s authors: There is no way to build offensive tools useful to the legitimate infosec industry while simultaneously preventing malicious actors from abusing them.

Source: https://github.com/Arno0x/WSC2

Tags: WebSocket C2WSC2