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:   https://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:
https://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:
https://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:       https://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
https://www.defensecode.com/ .

E-mail: defensecode[at]defensecode.com

Website: https://www.defensecode.com
Twitter: https://twitter.com/DefenseCode/