CVE-2021-37913
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to execute arbitrary system commands on HGiga OAKlouds mobile portal servers by injecting malicious commands into the IPv6 Gateway parameter. It affects systems running vulnerable versions of the OAKlouds mobile portal software. Attackers can gain complete control of affected systems without requiring any authentication.
💻 Affected Systems
- HGiga OAKlouds mobile portal
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to data theft, ransomware deployment, lateral movement within the network, and persistent backdoor installation.
Likely Case
Remote code execution resulting in system takeover, credential harvesting, and deployment of additional malware payloads.
If Mitigated
Limited impact if network segmentation prevents external access and strict input validation is implemented.
🎯 Exploit Status
Command injection vulnerabilities are typically easy to exploit. The CVSS 9.8 score indicates trivial exploitation with high impact.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in references, but HGiga has released security updates
Vendor Advisory: https://www.twcert.org.tw/tw/cp-132-5092-f88e2-1.html
Restart Required: Yes
Instructions:
1. Contact HGiga for the latest security patches. 2. Apply the patch to all affected OAKlouds mobile portal instances. 3. Restart the portal service. 4. Verify the fix by testing command injection attempts.
🔧 Temporary Workarounds
Network Access Restriction
linuxBlock external access to the OAKlouds mobile portal interface using firewall rules
iptables -A INPUT -p tcp --dport [portal_port] -s [trusted_networks] -j ACCEPT
iptables -A INPUT -p tcp --dport [portal_port] -j DROP
Input Validation WAF Rule
allImplement web application firewall rules to block malicious IPv6 gateway parameter values
🧯 If You Can't Patch
- Immediately isolate affected systems from internet access and restrict to internal trusted networks only
- Implement strict network segmentation and monitor all traffic to/from OAKlouds portal systems
🔍 How to Verify
Check if Vulnerable:
Test by attempting command injection in the IPv6 Gateway parameter field (e.g., using payloads like '; whoami' or '| id'). Only perform in controlled test environments.Check Version:
Check OAKlouds portal version through administrative interface or contact HGiga support for version identificationVerify Fix Applied:
After patching, attempt the same command injection tests and verify they are properly rejected or sanitized.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed login attempts followed by successful access
- Suspicious process creation from web server user
Network Indicators:
- Unusual outbound connections from OAKlouds portal server
- Traffic to known malicious IPs or domains
- Unexpected SSH/RDP connections originating from portal server
SIEM Query:
source="oaklouds-logs" AND (message="*IPv6*" OR message="*gateway*") AND (message="*;*" OR message="*|*" OR message="*`*")