CVE-2021-26622
📋 TL;DR
This critical vulnerability in Genian NAC allows remote attackers to execute arbitrary code with SYSTEM privileges on all connected nodes through server-side template injection (SSTI) and insufficient file name validation. All organizations using vulnerable versions of Genian NAC are affected, potentially giving attackers complete control over the entire NAC infrastructure.
💻 Affected Systems
- Genian NAC
📦 What is this software?
Genian Nac by Genians
Genian Nac by Genians
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of all NAC-connected nodes, allowing attackers to deploy ransomware, steal credentials, pivot to other network segments, and maintain persistent access across the entire infrastructure.
Likely Case
Attackers gain SYSTEM-level access to NAC nodes, enabling them to disable security controls, intercept network traffic, and compromise connected endpoints.
If Mitigated
If properly segmented and monitored, impact limited to NAC infrastructure with quick detection and containment preventing lateral movement.
🎯 Exploit Status
SSTI vulnerabilities typically have low exploitation complexity once the attack vector is identified
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in references, but vendor has released patches
Vendor Advisory: https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=66580
Restart Required: Yes
Instructions:
1. Contact Genian support for latest patches 2. Apply patches to all NAC components 3. Restart NAC services 4. Verify patch application
🔧 Temporary Workarounds
Network Segmentation
allIsolate NAC management interface from untrusted networks
Access Control
allRestrict access to NAC management interface to authorized IPs only
🧯 If You Can't Patch
- Immediately isolate NAC systems from production networks
- Implement strict network monitoring and alerting for suspicious NAC-related activity
🔍 How to Verify
Check if Vulnerable:
Check Genian NAC version against vendor's patched release informationCheck Version:
Check NAC management console or contact vendor for version verificationVerify Fix Applied:
Verify patch version installed and test for SSTI vulnerability using authorized security testing📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to NAC system
- Suspicious template processing errors
- Unexpected SYSTEM privilege operations
Network Indicators:
- Unusual outbound connections from NAC nodes
- Suspicious traffic to NAC management interface
SIEM Query:
source="nac_logs" AND (event="file_upload" OR event="template_execution") AND result="success"