CVE-2023-53929
📋 TL;DR
CVE-2023-53929 is a CSV injection vulnerability in phpMyFAQ 3.1.12 that allows authenticated users to inject malicious formulas into their profile names. When an administrator exports user data as a CSV file and opens it in spreadsheet software like Excel, these formulas can execute arbitrary code on the administrator's system. This affects all phpMyFAQ installations running the vulnerable version with authenticated user access.
💻 Affected Systems
- phpMyFAQ
📦 What is this software?
Phpmyfaq by Phpmyfaq
⚠️ Risk & Real-World Impact
Worst Case
An attacker gains remote code execution on an administrator's workstation when they open a malicious CSV export, potentially leading to full system compromise, data theft, or lateral movement within the network.
Likely Case
An authenticated user injects malicious formulas that execute when an administrator opens the CSV file in Excel, potentially compromising the administrator's workstation or stealing credentials.
If Mitigated
Administrators open CSV files in plain text editors or with formula execution disabled, preventing code execution while still allowing data export functionality.
🎯 Exploit Status
Exploit requires authenticated user access and administrator to open CSV file in vulnerable spreadsheet software. Public exploit code demonstrates the injection technique.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.1.13 or later
Vendor Advisory: https://www.phpmyfaq.de/
Restart Required: No
Instructions:
1. Backup your phpMyFAQ installation and database. 2. Download phpMyFAQ 3.1.13 or later from the official website. 3. Replace the existing installation files with the new version. 4. Verify the update was successful by checking the version in the admin panel.
🔧 Temporary Workarounds
Disable CSV export functionality
allTemporarily disable user data export to CSV files in phpMyFAQ admin settings
Modify phpMyFAQ configuration to remove CSV export options from admin interface
Sanitize user profile names
allAdd input validation to strip or escape special characters in user profile names
Add validation in user profile update functions to remove characters like =, +, -, @, |
🧯 If You Can't Patch
- Restrict user registration and profile modification to trusted users only
- Train administrators to open CSV exports in plain text editors or with formula execution disabled in spreadsheet software
🔍 How to Verify
Check if Vulnerable:
Check if phpMyFAQ version is 3.1.12 by viewing the version in the admin panel or checking the CHANGELOG file in the installation directory.Check Version:
Check phpMyFAQ admin panel or examine the CHANGELOG.md file in the installation directoryVerify Fix Applied:
After updating, verify the version shows 3.1.13 or later in the admin panel. Test by creating a test user with a malicious profile name (e.g., '=cmd|' /c calc'!A1') and attempting CSV export.📡 Detection & Monitoring
Log Indicators:
- User profile updates containing special characters like =, +, -, @, | in the name field
- CSV export operations from admin accounts
Network Indicators:
- HTTP POST requests to user profile update endpoints with suspicious payloads
SIEM Query:
source="phpmyfaq.log" AND ("update user" OR "profile update") AND ("=" OR "+" OR "-" OR "@" OR "|")