CVE-2019-18231
📋 TL;DR
This vulnerability in Advantech Spectre RT ERT351 routers allows attackers to intercept login credentials transmitted in clear text. Affected systems include versions 5.1.3 and earlier, exposing authentication data to network eavesdropping.
💻 Affected Systems
- Advantech Spectre RT ERT351
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access to industrial routers, potentially disrupting critical infrastructure operations or using the devices as network footholds.
Likely Case
Credential theft leading to unauthorized access to router configuration, network monitoring, or traffic manipulation.
If Mitigated
Limited impact if traffic is encrypted at higher network layers or if strong network segmentation isolates the devices.
🎯 Exploit Status
Exploitation requires network access to intercept traffic, but no authentication or special tools are needed beyond packet capture.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware versions after 5.1.3
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 updated firmware from Advantech support portal. 2. Backup current configuration. 3. Upload and install new firmware via web interface. 4. Restart router. 5. Verify version is updated.
🔧 Temporary Workarounds
Network segmentation
allIsolate affected routers to separate VLANs with strict access controls to limit exposure.
VPN tunnel for management
allRoute all management traffic through encrypted VPN tunnels to prevent credential interception.
🧯 If You Can't Patch
- Implement network-level encryption (IPsec/VPN) for all traffic to/from affected devices
- Deploy network monitoring to detect credential interception attempts and unauthorized access
🔍 How to Verify
Check if Vulnerable:
Use network packet capture tools (Wireshark/tcpdump) on the same network segment while logging into the router web interface. Check if login credentials appear in plain text.Check Version:
Login to router web interface and check System Information or Firmware Version page.Verify Fix Applied:
After patching, repeat packet capture test to confirm credentials are no longer transmitted in clear text.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts from new IP addresses
- Configuration changes from unusual locations
Network Indicators:
- ARP spoofing or unusual traffic patterns near router management interfaces
- Unencrypted HTTP POST requests containing 'password' fields
SIEM Query:
source="router_logs" AND (event_type="login" OR event_type="config_change") | stats count by src_ip🔗 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
