CVE-2023-39809
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on NVK iBSG v3.5 systems by injecting malicious commands into the system_hostname parameter. Attackers can gain full control of affected systems, potentially compromising the entire network infrastructure. Organizations using NVK iBSG v3.5 for network management are affected.
💻 Affected Systems
- NVK iBSG
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover leading to data exfiltration, ransomware deployment, lateral movement across network, and persistent backdoor installation.
Likely Case
Unauthorized command execution leading to service disruption, configuration changes, and credential harvesting from the compromised system.
If Mitigated
Limited impact with proper network segmentation, command filtering, and least privilege access controls in place.
🎯 Exploit Status
Command injection vulnerabilities are typically easy to exploit once the vulnerable parameter is identified. Authentication status unknown from provided information.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown - vendor websites provided but no specific advisory found
Restart Required: No
Instructions:
1. Contact NVK INTER CO., LTD. for patch availability
2. If patch exists, download from vendor portal
3. Apply patch following vendor instructions
4. Verify fix by testing the vulnerable endpoint
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement server-side validation to reject malicious characters in system_hostname parameter
Implement regex validation: ^[a-zA-Z0-9\-\.]+$ for hostnames
Use parameterized functions for system calls
Network Access Control
linuxRestrict access to the management interface using firewall rules
iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Isolate affected systems in a dedicated VLAN with strict firewall rules
- Implement web application firewall (WAF) with command injection protection rules
🔍 How to Verify
Check if Vulnerable:
Test the /manage/network-basic.php endpoint with command injection payloads in system_hostname parameter (e.g., system_hostname=test;id)Check Version:
Check web interface footer or system information page for version detailsVerify Fix Applied:
Attempt exploitation with same payloads and verify no command execution occurs📡 Detection & Monitoring
Log Indicators:
- Unusual system commands in web server logs
- Multiple failed login attempts followed by command injection attempts
- Suspicious characters (; & | ` $) in POST parameters
Network Indicators:
- POST requests to /manage/network-basic.php with shell metacharacters
- Outbound connections from iBSG system to unexpected destinations
SIEM Query:
source="web_logs" AND uri="/manage/network-basic.php" AND (param="system_hostname" AND value MATCHES "[;&|`$()]+")