CVE-2019-18235
📋 TL;DR
This vulnerability in Advantech Spectre RT ERT351 routers allows attackers to bypass authentication through brute-force password attacks due to insufficient login parameters. Affected organizations using these industrial routers for critical infrastructure face potential complete system compromise. The vulnerability affects versions 5.1.3 and earlier.
💻 Affected Systems
- Advantech Spectre RT ERT351 Industrial Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of industrial control systems, unauthorized access to critical infrastructure networks, potential manipulation of physical processes, and data exfiltration.
Likely Case
Unauthorized administrative access to router web interface, configuration changes, network traffic interception, and lateral movement into connected industrial systems.
If Mitigated
Limited impact with proper network segmentation, strong authentication controls, and monitoring in place.
🎯 Exploit Status
Brute-force attacks require no authentication and can be automated with standard tools. The vulnerability is in the authentication mechanism itself.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version 5.1.4 or later
Vendor Advisory: https://ep.advantech-bb.cz/support/router-models/download/511/sa-2021-01-fw-5.1.3-and-older-en.pdf
Restart Required: Yes
Instructions:
1. Download firmware version 5.1.4 or later from Advantech support portal. 2. Backup current configuration. 3. Upload new firmware via web interface. 4. Apply configuration backup. 5. Verify successful update and functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate router management interface from untrusted networks
Access Control Lists
linuxRestrict access to router web interface to trusted IP addresses only
# Example firewall rule to restrict access
# iptables -A INPUT -p tcp --dport 80 -s trusted_ip -j ACCEPT
# iptables -A INPUT -p tcp --dport 443 -s trusted_ip -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
- Implement strict network segmentation to isolate router from untrusted networks
- Deploy intrusion detection systems to monitor for brute-force attempts and unauthorized access
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface or CLI. If version is 5.1.3 or earlier, the device is vulnerable.Check Version:
# Via web interface: System > Status > Firmware Version
# Via CLI: show versionVerify Fix Applied:
Verify firmware version is 5.1.4 or later. Test authentication with incorrect credentials to ensure proper rate limiting and lockout mechanisms.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts from single IP
- Successful login from unusual IP addresses
- Configuration changes outside maintenance windows
Network Indicators:
- High volume of HTTP/HTTPS requests to router login page
- Traffic patterns consistent with brute-force tools
SIEM Query:
source="router_logs" (event="authentication failed" count>10 within 5min) OR (event="configuration changed" user!="authorized_user")🔗 References
- https://ep.advantech-bb.cz/support/router-models/download/511/sa-2021-01-fw-5.1.3-and-older-en.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-054-03
- https://ep.advantech-bb.cz/support/router-models/download/511/sa-2021-01-fw-5.1.3-and-older-en.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-054-03
