Building a Windows Implant without Artificial Intelligence: A C++ Guide

Published Date: 27/05/2024      

Learn how to develop a Windows implant using C++ without relying on artificial intelligence.

 Artificial intelligence (AI) and machine learning are buzzwords in the cybersecurity industry, but they can also be used for malicious purposes, such as malware development. This article focuses on building a Windows implant without AI, instead using C++ and WinINet APIs for HTTP communication.

As a cybersecurity professional, I've written about malware development for SANS, SEC670. Many of my students have discussed using AI to assist with code generation, but the resulting code often lacks proper error checking, bad parameters, and incorrect API calls. I understand the urge to use AI-generated code, but it needs to get much better.

When it comes to HTTP communication, there are two primary API families: WinHttp and WinINet. Microsoft has documented both families and provides a table about their features. In this article, we'll showcase WinINet with a basic HTTP POST request.

First, let's create an Internet session using the `InternetOpen` API. The parameters for the function are straightforward, but the details of each can be found on Microsoft's website. Next, we'll create a handle for the Internet connection using `InternetConnect`. Documentation for its details can be found by reading Microsoft documentation.

To make a POST request, we'll use `HttpOpenRequest`. The function name might make you think it's part of the WinHttp library, but it's not. The call is going to be made for a POST request to the route/register so that the implant can check in.

After calling `HttpSendRequest`, the packet is gone. It's useful to have Wireshark running to validate the data. This example is extremely simple and just sends off some raw data, but you could send JSON encrypted and/or Base64-encoded data, too.

To receive a response, we'll use `InternetReadFile`. This API is used to read data from the response. We can store the data in a byte vector or a string, depending on our needs.

This article provides a simple example of how to develop a Windows implant using C++ without relying on artificial intelligence. By understanding how to use WinINet APIs for HTTP communication, you can create your own implant to perform various tasks.