CVE-2021-32243
📋 TL;DR
CVE-2021-32243 is an authenticated file upload vulnerability in FOGProject that allows remote code execution. Attackers with valid credentials can upload malicious files to execute arbitrary commands on the server. This affects FOGProject administrators and users with upload privileges.
💻 Affected Systems
- FOGProject
📦 What is this software?
Fogproject by Fogproject
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to execute arbitrary commands as the web server user, potentially leading to lateral movement, data exfiltration, or complete system takeover.
Likely Case
Unauthorized file upload leading to web shell deployment, allowing persistent access and further exploitation of the server.
If Mitigated
Limited impact if proper file upload validation and authentication controls are in place, potentially only allowing file upload without execution.
🎯 Exploit Status
Exploitation requires valid credentials but is straightforward once authenticated. Public proof-of-concept code exists in GitHub issues.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.5.10 and later
Vendor Advisory: https://github.com/FOGProject/fogproject/issues/422
Restart Required: No
Instructions:
1. Backup current FOGProject installation. 2. Download latest version from official repository. 3. Follow upgrade instructions in FOGProject documentation. 4. Verify file upload functionality is properly validated.
🔧 Temporary Workarounds
Restrict File Upload Types
allImplement strict file type validation for uploads, allowing only specific extensions.
# Configure web server to block execution of uploaded files in upload directories
# Example Apache: <Directory /path/to/uploads>\n php_flag engine off\n RemoveHandler .php .phtml .php3 .php4 .php5 .php7\n RemoveType .php .phtml .php3 .php4 .php5 .php7\n</Directory>
Implement Web Application Firewall Rules
allAdd WAF rules to detect and block malicious file upload patterns.
# ModSecurity rule example: SecRule FILES "@rx \\.(php|phtml|php3|php4|php5|php7)$" \"id:1001,phase:2,deny,msg:'Blocked malicious file upload'\"
🧯 If You Can't Patch
- Implement strict access controls and limit file upload privileges to essential users only.
- Monitor upload directories for suspicious files and implement file integrity monitoring.
🔍 How to Verify
Check if Vulnerable:
Check FOGProject version via web interface or by examining installation files. Versions 1.5.9 and earlier are vulnerable.Check Version:
Check FOGProject web interface dashboard or examine /var/www/html/fog/commons/text.php for version information.Verify Fix Applied:
Verify installation is version 1.5.10 or later and test file upload functionality with restricted file types.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to FOGProject directories
- Files with executable extensions (.php, .phtml) in upload directories
- Multiple failed upload attempts followed by successful upload
Network Indicators:
- HTTP POST requests to FOGProject upload endpoints with executable file content
- Subsequent requests to uploaded files in unusual locations
SIEM Query:
source="*fogproject*" AND (url="*upload*" OR url="*.php*") AND (http_method="POST" OR file_extension="php")