CVE-2020-25177
📋 TL;DR
A stack-based buffer overflow vulnerability in WECON PLC Editor versions 1.3.8 and earlier allows attackers to execute arbitrary code by sending specially crafted packets. This affects industrial control systems using WECON PLC programming software, potentially compromising PLC logic and operations.
💻 Affected Systems
- WECON PLC Editor
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to modify PLC logic, disrupt industrial processes, cause physical damage, or establish persistent access to industrial networks.
Likely Case
Remote code execution leading to PLC program manipulation, production disruption, data theft, or lateral movement within industrial networks.
If Mitigated
Limited impact with proper network segmentation and access controls, potentially only affecting isolated engineering workstations.
🎯 Exploit Status
Exploitation requires network access to the PLC Editor service port (typically 502/TCP or similar).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 1.3.9 or later
Vendor Advisory: https://us-cert.cisa.gov/ics/advisories/icsa-20-310-01
Restart Required: Yes
Instructions:
1. Download latest version from WECON website. 2. Uninstall current version. 3. Install updated version. 4. Restart system.
🔧 Temporary Workarounds
Network Segmentation
allIsolate PLC programming workstations from production networks and internet access.
Firewall Rules
windowsBlock access to PLC Editor service ports from untrusted networks.
netsh advfirewall firewall add rule name="Block PLC Editor" dir=in action=block protocol=TCP localport=502
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected systems
- Deploy application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Help > About in WECON PLC Editor for version number. Versions 1.3.8 and earlier are vulnerable.Check Version:
Not applicable - check via application GUIVerify Fix Applied:
Verify version is 1.3.9 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Unusual network connections to PLC Editor service port
- Multiple failed connection attempts followed by successful connection
Network Indicators:
- Unusual traffic patterns to port 502/TCP or PLC Editor service port
- Large or malformed packets sent to PLC Editor
SIEM Query:
source_ip="*" AND dest_port=502 AND (packet_size>threshold OR protocol_anomaly=true)