CVE-2020-26678
📋 TL;DR
CVE-2020-26678 is a remote code execution vulnerability in vFairs 3.3 that allows authenticated users to upload malicious PHP files via profile picture functionality. This affects all organizations using vFairs 3.3 for virtual conferences or events. Attackers can execute arbitrary code on the server, potentially compromising the entire system.
💻 Affected Systems
- vFairs
📦 What is this software?
Vfairs by Vfairs
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise leading to data theft, lateral movement to other systems, ransomware deployment, or complete system takeover.
Likely Case
Attacker gains shell access to the web server, steals sensitive attendee/organizer data, defaces the event platform, or installs backdoors.
If Mitigated
With proper file upload restrictions and web application firewalls, exploitation attempts are blocked and logged.
🎯 Exploit Status
Exploitation requires authenticated user access but is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.4 or later
Vendor Advisory: https://www.vfairs.com/security
Restart Required: Yes
Instructions:
1. Backup current vFairs installation and database. 2. Download and install vFairs 3.4 or later from vendor portal. 3. Apply the update following vendor instructions. 4. Restart web server services. 5. Verify functionality.
🔧 Temporary Workarounds
Restrict PHP file uploads
allConfigure web server to block PHP file uploads via profile picture functionality
# For Apache: Add to .htaccess
<FilesMatch "\.(php|php5|php7|phtml)$">
Order Allow,Deny
Deny from all
</FilesMatch>
# For Nginx: Add to server block
location ~ \.php$ {
deny all;
}
Implement file type validation
allAdd server-side validation to only allow image file types (jpg, png, gif)
# Example PHP validation
$allowed_types = ['image/jpeg', 'image/png', 'image/gif'];
if (!in_array($_FILES['profile_pic']['type'], $allowed_types)) {
die('Invalid file type');
}
🧯 If You Can't Patch
- Implement strict file upload validation on web application firewall
- Disable profile picture upload functionality entirely
🔍 How to Verify
Check if Vulnerable:
Check vFairs version in admin panel or via /api/v1/version endpoint. If version is 3.3, system is vulnerable.Check Version:
curl -s https://your-vfairs-instance/api/v1/version | grep versionVerify Fix Applied:
Verify version is 3.4 or later and test that PHP files cannot be uploaded via profile picture feature.📡 Detection & Monitoring
Log Indicators:
- PHP file uploads via profile picture endpoints
- Unusual file uploads with .php extensions
- POST requests to /api/v1/profiles with PHP files
Network Indicators:
- HTTP POST requests with PHP file content to upload endpoints
- Subsequent HTTP requests to uploaded PHP files
SIEM Query:
source="web_logs" AND (uri_path="/api/v1/profiles" OR uri_path="/upload") AND (file_extension="php" OR content_type="application/x-php")🔗 References
- http://vfairs.com
- https://api.vfairs.com/v1/profiles
- https://www.huntress.com/blog/zero-day-vulnerabilities-in-popular-event-management-platforms-could-leave-msps-open-to-attack
- http://vfairs.com
- https://api.vfairs.com/v1/profiles
- https://www.huntress.com/blog/zero-day-vulnerabilities-in-popular-event-management-platforms-could-leave-msps-open-to-attack
