CVE-2021-40848
📋 TL;DR
This CVE describes a CSV injection vulnerability in Mahara e-portfolio software where exported CSV files could contain malicious formulas that spreadsheet programs might execute. This allows attackers to potentially execute commands on a victim's local machine when they open the CSV file. Affected users are anyone using vulnerable Mahara versions who exports and opens CSV files.
💻 Affected Systems
- Mahara
📦 What is this software?
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
Mahara by Mahara
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution on victim's machine when they open a malicious CSV file in a vulnerable spreadsheet application, potentially leading to full system compromise.
Likely Case
Local command execution or formula injection in spreadsheet applications, potentially stealing data or executing malicious scripts on the user's system.
If Mitigated
No impact if users don't open CSV files from untrusted sources or if spreadsheet applications have security features enabled to block formula execution.
🎯 Exploit Status
Exploitation requires user interaction (opening CSV file) and depends on spreadsheet application behavior.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Mahara 20.04.5, 20.10.3, 21.04.2, or 21.10.0
Vendor Advisory: https://mahara.org/interaction/forum/topic.php?id=8950
Restart Required: No
Instructions:
1. Backup your Mahara installation and database. 2. Download the patched version from Mahara's official website. 3. Follow Mahara's upgrade instructions for your specific version. 4. Verify the upgrade completed successfully.
🔧 Temporary Workarounds
Disable CSV Export
allTemporarily disable CSV export functionality in Mahara to prevent exploitation.
Edit Mahara configuration to disable CSV export features
User Education
allEducate users to only open CSV files from trusted sources and to use text editors instead of spreadsheet applications for unknown files.
🧯 If You Can't Patch
- Implement strict access controls to limit who can export CSV files
- Deploy endpoint protection that blocks execution of formulas in CSV files
🔍 How to Verify
Check if Vulnerable:
Check your Mahara version via admin panel or by examining version files. If version is before 20.04.5, 20.10.3, 21.04.2, or 21.10.0, you are vulnerable.Check Version:
Check Mahara admin panel or examine version.php file in Mahara installation directory.Verify Fix Applied:
After patching, verify version shows 20.04.5, 20.10.3, 21.04.2, 21.10.0 or later. Test CSV export functionality to ensure it works without formula injection.📡 Detection & Monitoring
Log Indicators:
- Unusual CSV export patterns
- Multiple failed export attempts
- Large CSV file exports
Network Indicators:
- CSV file downloads from Mahara instance
- Unusual file transfer patterns
SIEM Query:
source="mahara" AND (event="csv_export" OR file_type="csv")