[waraxe-2013-SA#098] - Directory Traversal Vulnerabilities in OpenCart 1.5.5.1

Author: Janek Vind "waraxe"
Date: 19. March 2013
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-98.html

Description of vulnerable software:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

OpenCart is a turn-key ready "out of the box" shopping cart solution.
You simply install, select your template, add products and your ready to start
accepting orders.

http://www.opencart.com/

Affected are all OpenCart versions, from 1.4.7 to 1.5.5.1, maybe older too.

###############################################################################
1. Directory Traversal Vulnerabilities in "filemanager.php"
###############################################################################

Reason: insufficient sanitization of user-supplied data
Attack vectors:
1. user-supplied POST parameters "directory", "name", "path", "from", "to"
Preconditions:
1. Logged in as admin with filemanager access privileges

Script "filemanager.php" offers for OpenCart admins various file related services:
directory listing and creation, image file listing, file copy/move/unlink, upload,
image resize. By the design OpenCart admin can manage files and directories only
inside specific subdirectory "image/data/". It means, that even if you have
OpenCart admin privileges, you still are not suppose to get access to the files
and directories below "image/data/". So far, so good.
But what about directory traversal? Let's have a look at the source code.

PHP script "admin/controller/common/filemanager.php" line 66:
------------------------[ source code start ]----------------------------------
public function directory() {
$json = array();

if (isset($this->request->post['directory'])) {
$directories = glob(rtrim(DIR_IMAGE . 'data/' .
str_replace('../', '', $this->request->post['directory']), '/') .
'/*', GLOB_ONLYDIR);

if ($directories) {
$i = 0;

foreach ($directories as $directory) {
$json[$i]['data'] = basename($directory);
$json[$i]['attributes']['directory'] =
utf8_substr($directory, strlen(DIR_IMAGE . 'data/'));
...

$this->response->setOutput(json_encode($json));
------------------------[ source code end ]------------------------------------

We can see, that directory traversal is prevented by removing "../" substrings
from user submitted parameters. At first look this seems to be secure enough -
if we can't use "../", then directory traversal is impossible, right?
Deeper analysis shows couple of shortcomings in specific filtering method.
First problem - if OpenCart is hosted on Windows platform, then it's possible
to use ".." substring for directory traversal.

Test (parameter "token" must be valid):
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/oc1551/admin/index.php?route=common/filemanager/directory&token=92aa6ac32b4c8e7a175c3dc9f7754d25" method="post">
<input type="hidden" name="directory" value="......">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

Server response is in JSON format and contains listing of subdirectories outside
of OpenCart main directory.

Second problem - filtering with "str_replace" can be tricked by using custom
strings. If we use "..././" substring, then after filtering in becomes "../".
So it appears, that implemented anti-traversal code is ineffective and can
be bypassed.

Test (parameter "token" must be valid):
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/oc1551/admin/index.php?route=common/filemanager/directory&token=92aa6ac32b4c8e7a175c3dc9f7754d25" method="post">
<input type="hidden" name="directory" value="..././..././..././..././">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

Server response is exactly same as in previous test - information about directory
structure outside of OpenCart main directory has been disclosed.

PHP script "filemanager.php" contains 14 uses of "str_replace('../', ''," code.
Most of the public functions in "filemanager.php" are affected by directory
traversal vulnerability:

public function directory() -> listing of subdirectories
public function files() -> listing of image files
public function create() -> creation of new directories
public function delete() -> deletion of arbitrary files and directories
public function move() -> renaming of files or directories
public function copy() -> copying of files or directories
public function rename() -> renaming of files or directories
public function upload() -> uploading of image or flash files

Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

come2waraxe@yahoo.com
Janek Vind "waraxe"

Waraxe forum: http://www.waraxe.us/forums.html
Personal homepage: http://www.janekvind.com/
Random project: http://albumnow.com/
---------------------------------- [ EOF ] ------------------------------------

Published on: 2013-03-19 (27088 reads)

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