CVE-2020-10621
📋 TL;DR
This vulnerability allows unauthenticated attackers to upload and execute arbitrary files on Advantech WebAccess/NMS systems. It affects all versions prior to 3.0.2, enabling remote code execution on vulnerable installations.
💻 Affected Systems
- Advantech WebAccess/NMS
📦 What is this software?
Webaccess\/nms by Advantech
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install malware, pivot to other systems, disrupt operations, or deploy ransomware across the network.
Likely Case
Attackers gain initial foothold on the network, deploy backdoors or cryptocurrency miners, and potentially move laterally to other industrial control systems.
If Mitigated
Attackers are blocked at network perimeter or detected during initial reconnaissance attempts before exploitation.
🎯 Exploit Status
Exploitation is straightforward with publicly available proof-of-concept code. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.2
Vendor Advisory: https://www.advantech.com/support/details/firmware?id=1KXK3B3K3K3K3K3K3K3K3K3K3K3K3K3K
Restart Required: Yes
Instructions:
1. Download WebAccess/NMS version 3.0.2 from Advantech support portal. 2. Backup current configuration. 3. Run installer to upgrade. 4. Restart the WebAccess/NMS service. 5. Verify version shows 3.0.2.
🔧 Temporary Workarounds
Network Segmentation
allIsolate WebAccess/NMS systems from internet and restrict internal access to authorized networks only.
Web Application Firewall Rules
allBlock file upload functionality at the WAF level to prevent exploitation.
# Example WAF rule to block file uploads to vulnerable endpoints
SecRule REQUEST_URI "@rx /upload" "id:1001,phase:1,deny"
🧯 If You Can't Patch
- Implement strict network access controls to limit connections to WebAccess/NMS only from authorized management stations.
- Deploy endpoint detection and response (EDR) solutions to monitor for suspicious file creation and execution activities.
🔍 How to Verify
Check if Vulnerable:
Check WebAccess/NMS version in administration panel or via registry: HKEY_LOCAL_MACHINE\SOFTWARE\Advantech\WebAccess\NMS\VersionCheck Version:
reg query "HKLM\SOFTWARE\Advantech\WebAccess\NMS" /v VersionVerify Fix Applied:
Confirm version is 3.0.2 or higher in administration interface and test that file upload functionality is properly restricted.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to WebAccess/NMS endpoints
- Execution of unexpected processes by WebAccess/NMS service account
- Creation of suspicious files in WebAccess/NMS directories
Network Indicators:
- HTTP POST requests to /upload endpoints with executable file extensions
- Outbound connections from WebAccess/NMS server to unknown external IPs
SIEM Query:
source="webaccess_logs" AND (uri_path="/upload" OR file_extension IN ("exe", "bat", "ps1", "sh"))