CVE-2023-2666
📋 TL;DR
CVE-2023-2666 is an allocation of resources without limits vulnerability in Froxlor server management panel. Attackers can cause resource exhaustion (memory/CPU) by sending specially crafted requests, potentially leading to denial of service. All Froxlor installations prior to version 2.0.16 are affected.
💻 Affected Systems
- Froxlor
📦 What is this software?
Froxlor by Froxlor
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to resource exhaustion, affecting all hosted websites and services managed through Froxlor.
Likely Case
Degraded performance or temporary service interruptions for Froxlor panel and managed services.
If Mitigated
Minimal impact with proper rate limiting and resource monitoring in place.
🎯 Exploit Status
The vulnerability allows unauthenticated resource exhaustion attacks. While no public PoC exists, the simple nature makes weaponization likely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.16
Vendor Advisory: https://github.com/froxlor/froxlor/commit/1679675aa1c29d24344dd2e091ff252accb111d6
Restart Required: Yes
Instructions:
1. Backup current Froxlor installation and database. 2. Download Froxlor 2.0.16 or later from official repository. 3. Replace existing files with new version. 4. Run update.php script. 5. Restart web server (Apache/Nginx).
🔧 Temporary Workarounds
Rate Limiting via Web Server
linuxImplement request rate limiting at web server level to prevent resource exhaustion attacks.
# For Nginx: limit_req_zone $binary_remote_addr zone=froxlor:10m rate=10r/s;
# For Apache: Use mod_ratelimit or mod_security rules
Network Access Restriction
linuxRestrict Froxlor panel access to trusted IP addresses only.
# In web server config: Allow from 192.168.1.0/24
# Or use firewall: iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
🧯 If You Can't Patch
- Implement strict rate limiting at network perimeter or web server level.
- Monitor system resources (memory, CPU) and set up alerts for abnormal consumption patterns.
🔍 How to Verify
Check if Vulnerable:
Check Froxlor version in admin panel or via command: grep 'Version' /var/www/froxlor/lib/version.phpCheck Version:
grep "\$version" /var/www/froxlor/lib/version.php | cut -d"'" -f2Verify Fix Applied:
Confirm version is 2.0.16 or higher and test that resource exhaustion attempts are properly throttled.📡 Detection & Monitoring
Log Indicators:
- High frequency of requests to Froxlor endpoints
- Web server error logs showing 429 (Too Many Requests) or 503 (Service Unavailable) errors
- System logs showing high memory/CPU usage by web server processes
Network Indicators:
- Unusual request patterns to Froxlor admin interface
- Multiple rapid connections from single IP addresses
SIEM Query:
source="web_server_logs" | where url_path contains "/froxlor/" | stats count by src_ip | where count > 100