WordPress Ultimate Form Builder Lite 1.3.7 XSS / SQL Injection

`DefenseCode ThunderScan SAST Advisory: WordPress Ultimate Form Builder  
Lite Plugin Multiple Vulnerabilities (XSS and SQLi)  
  
  
Advisory ID: DC-2018-05-009  
Advisory Title: WordPress Ultimate Form Builder Lite Plugin Multiple  
Vulnerabilities (XSS and SQLi)  
Advisory URL: http://www.defensecode.com/advisories.php  
Software: WordPress Ultimate Form Builder Lite plugin  
Language: PHP  
Version: 1.3.7 and below  
Vendor Status: Vendor contacted, update released  
Release Date: 2018/06/12  
Risk: Medium  
  
  
  
1. General Overview  
===================  
During the security audit of Ultimate Form Builder Lite plugin for  
WordPress CMS, multiple vulnerabilities were 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, Ultimate Form Builder Lite is a  
free WordPress Plugin which allows you to create various contact forms  
with drag and drop form builder. Its fun because a you can create,  
customize and build the beautiful forms for your site on your own,  
receive contact email on any desired email address and store the form  
entries in your database which can be exported to CSV for your use via  
pluginas backend.  
  
According to wordpress.org, it has more than 40,000 active installs.  
  
Homepage:  
https://wordpress.org/plugins/ultimate-form-builder-lite/  
  
  
3. Vulnerability Description  
============================  
During the security analysis, ThunderScan discovered  
Cross-Site Scripting and SQL injection vulnerabilities in Ultimate  
Form Builder Lite 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.  
  
The easiest way to reproduce the SQL injection vulnerability is to  
visit the provided URL while being logged in as administrator or  
another user that is authorized to access the plugin settings page.  
Users that do not have full administrative privileges could abuse the  
database access the vulnerability provides to either escalate their  
privileges or obtain and modify database contents they were not  
supposed to be able to.  
  
3.1 Cross-Site Scripting  
Vulnerable Function: echo()  
Vulnerable Variable: $_GET['form_id']  
Vulnerable URL:  
http://vulnerablesite.com/wp-admin/admin.php?page=ufbl&action=edit-form&form_id=1"><script>alert(42)</script>  
File:  
ultimate-form-builder-lite/inc/views/backend/form-builder.php  
---------  
10 <div class="ufbl-shortcode-display-wrap">Shortcode: <input  
type="text" onfocus="this.select();" readonly="readonly" value="[ufbl  
form_id="<?php echo $_GET['form_id']?>"]"  
class="shortcode-in-list-table wp-ui-text-highlight code"></div>  
---------  
  
3.2 SQL injection  
Vulnerable Function: $wpdb->get_row()  
Vulnerable Variable: $_POST['entry_id']  
Vulnerable URL: http://vulnerablesite.com/wp-admin/admin-ajax.php  
Vulnerable POST body:  
entry_id=1&_wpnonce=xxx&action=ufbl_get_entry_detail_action  
File:  
ultimate-form-builder-lite/ultimate-form-builder-lite.php  
---------  
369 $entry_id = sanitize_text_field( $_POST['entry_id'] );  
...  
370 $entry_row = $this->model->get_entry_detail( $entry_id );  
---------  
File: ultimate-form-builder-lite\classes\ufbl-model.php  
---------  
243 public static function get_entry_detail( $entry_id ) {  
...  
248 $entry_row = $wpdb->get_row( "SELECT * FROM $entry_table INNER  
JOIN $form_table ON $entry_table.form_id = $form_table.form_id WHERE  
$entry_table.entry_id = $entry_id", 'ARRAY_A' );  
---------  
  
  
4. Solution  
===========  
After the vulnerabilities were reported the vendor resolved the  
security issues. All users are strongly advised to update WordPress  
Ultimate Form Builder Lite plugin to the latest available version.  
  
  
5. Credits  
==========  
Discovered by Neven Biruski using DefenseCode ThunderScan source code  
security analyzer.  
  
  
6. Disclosure Timeline  
======================  
2018/06/01 Vulnerabilities discovered  
2018/06/06 Vendor contacted  
2018/06/08 Vendor responded  
2018/06/12 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/  
`