WordPress No External Links 3.5.17 Cross Site Scripting

`  
DefenseCode ThunderScan SAST Advisory  
WordPress No External Links Plugin  
Security Vulnerability  
  
  
Advisory ID: DC-2017-01-022  
Advisory Title: WordPress No External Links Plugin Security  
Vulnerability  
Advisory URL: http://www.defensecode.com/advisories.php  
Software: WordPress No External Links Plugin  
Language: PHP  
Version: 3.5.17 and below  
Vendor Status: Vendor contacted, update released  
Release Date: 2017/05/29  
Risk: Medium  
  
  
  
1. General Overview  
===================  
During the security audit of No External Links plugin for WordPress  
CMS, security vulnerability was discovered using DefenseCode  
ThunderScan application source code security analysis platform.  
  
More information about ThunderScan is available at URL:  
http://www.defensecode.com  
  
  
2. Software Overview  
====================  
According to the plugin developers, this plugin has many cool  
features a outgoing clicks stats, fulllink masking, custom redirects,  
masking links to digital short code and base64 encoding and so on. It  
is designed for specialists who sell different kind of advertisment on  
their web site (for example, with sape system) and care about the  
number of outgoing links that can be found by search engines. It has  
more than 20,000 downloads on wordpress.org.  
  
Homepage:  
https://wordpress.org/plugins/wp-noexternallinks/  
http://jehy.ru/articles/2008/10/05/wordpress-plugin-no-external-links/  
  
  
3. Vulnerability Description  
==================================  
During the security analysis, ThunderScan discovered Cross-Site  
Scripting vulnerability in No External Links WordPress plugin.  
  
The Cross-Site Scripting vulnerability can enable the attacker to  
construct the URL that contains malicious JavaScript code. If the  
administrator of the site makes a request to such an URL, the  
attacker's code will be executed, with unrestricted access to the  
WordPress site in question. The attacker can entice the administrator  
to visit the URL in various ways, including sending the URL by email,  
posting it as a part of the comment on the vulnerable site or another  
forum.  
  
3.1. Cross-Site Scripting  
Function: echo  
Variable: $_REQUEST['date1'], $_REQUEST['date2']  
Sample URL:   
http://vulnerablesite.com/wp-admin/options-general.php?page=wp-noexternallinks%2Fwp-noexternallinks-options.php&action=stats&date1="><script>alert(1)</script>  
Sample URL:   
http://vulnerablesite.com/wp-admin/options-general.php?page=wp-noexternallinks%2Fwp-noexternallinks-options.php&action=stats&date2="><script>alert(1)</script>  
File: wp-noexternallinks\wp-noexternallinks-options.php  
---------  
125 $date1 = $_REQUEST['date1'];  
...  
129 $date2 = $_REQUEST['date2'];  
...  
134 <input type="text" name="date1" value="<?php echo $date1;  
?>"> <?php _e('to', 'wp-noexternallinks'); ?>  
135 <input type="text" name="date2" value="<?php echo $date2;  
?>"><input type="submit"  
---------  
  
  
4. Solution  
===========  
Vendor resolved the security issues after we reported the  
vulnerability. All users are strongly advised to update WordPress No  
External Links plugin to the latest available version.  
  
  
5. Credits  
==========  
Discovered with DefenseCode ThunderScan source code security analyzer  
by Neven Biruski.  
  
  
6. Disclosure Timeline  
======================  
2017/04/06 Vendor contacted  
2017/04/13 Vendor responded, update released  
2017/05/29 Advisory released to the public  
  
  
7. About DefenseCode  
====================  
DefenseCode L.L.C. delivers products and services designed to analyze  
and test web, desktop and mobile applications for security  
vulnerabilities.  
  
DefenseCode ThunderScan is a SAST (Static Application Security  
Testing, WhiteBox Testing) solution for performing extensive security  
audits of application source code. ThunderScan SAST performs fast and  
accurate analyses of large and complex source code projects delivering  
precise results and low false positive rate.  
  
DefenseCode WebScanner is a DAST (Dynamic Application Security  
Testing, BlackBox Testing) solution for comprehensive security audits  
of active web applications. WebScanner will test a website's security  
by carrying out a large number of attacks using the most advanced  
techniques, just as a real attacker would.  
  
Subscribe for free software trial on our website  
http://www.defensecode.com/ .  
  
E-mail: defensecode[at]defensecode.com  
  
Website: http://www.defensecode.com  
Twitter: https://twitter.com/DefenseCode/  
  
  
  
`