CVE-2018-9035
📋 TL;DR
This CSV injection vulnerability in the Contact Form 7 to Database Extension plugin allows attackers to embed malicious spreadsheet formulas into exported CSV files. When victims open these files in spreadsheet applications like Excel, the formulas execute, potentially leading to data theft or system compromise. WordPress sites using the vulnerable plugin version are affected.
💻 Affected Systems
- Contact Form 7 to Database Extension WordPress plugin
📦 What is this software?
Contact Form 7 To Database Extension by Contact Form 7 To Database Extension Project
View all CVEs affecting Contact Form 7 To Database Extension →
⚠️ Risk & Real-World Impact
Worst Case
Attackers could execute arbitrary code on victim machines when CSV files are opened in vulnerable spreadsheet applications, leading to full system compromise, data exfiltration, or ransomware deployment.
Likely Case
Attackers inject formulas that steal credentials, personal data, or execute commands when users open exported CSV files in Excel or similar applications.
If Mitigated
With proper controls, the impact is limited to formula execution within spreadsheet applications only, not server-side code execution.
🎯 Exploit Status
Exploitation requires victims to open malicious CSV files in vulnerable spreadsheet applications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.10.33 and later
Vendor Advisory: https://wordpress.org/plugins/contact-form-7-to-database-extension/#developers
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find 'Contact Form 7 to Database Extension'. 4. Click 'Update Now' if available, or manually update to version 2.10.33+. 5. Verify update completes successfully.
🔧 Temporary Workarounds
Disable CSV Export
allTemporarily disable CSV export functionality in plugin settings
Input Sanitization
linuxAdd custom validation to sanitize form inputs before CSV export
Add PHP filter: preg_replace('/^[=+@-]/', "'", $input)
🧯 If You Can't Patch
- Restrict access to CSV export functionality to trusted users only
- Educate users to never open CSV files from untrusted sources in spreadsheet applications
🔍 How to Verify
Check if Vulnerable:
Check plugin version in WordPress admin under Plugins > Installed PluginsCheck Version:
wp plugin list --name='Contact Form 7 to Database Extension' --field=versionVerify Fix Applied:
Verify plugin version is 2.10.33 or higher and test CSV export with formula payloads📡 Detection & Monitoring
Log Indicators:
- CSV export requests with formula characters (=, +, @, -) in form data
Network Indicators:
- HTTP requests to ExportToCsvUtf8.php with suspicious payloads
SIEM Query:
source="wordpress" AND uri="*ExportToCsvUtf8.php*" AND (form_data="=*" OR form_data="+*" OR form_data="@*")