CVE-2020-20486
📋 TL;DR
CVE-2020-20486 is a stack buffer overflow vulnerability in IEC104 v1.0's Iec10x_Sta_Addr parameter that allows remote attackers to execute arbitrary code or cause denial of service. This affects industrial control systems and SCADA environments using the IEC 60870-5-104 protocol implementation. Organizations using IEC104 v1.0 for power system automation and industrial communication are at risk.
💻 Affected Systems
- IEC104 v1.0
📦 What is this software?
Iec104 by Iec104 Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, manipulation of industrial processes, or permanent damage to critical infrastructure equipment.
Likely Case
Denial of service causing disruption to industrial operations, loss of monitoring capabilities, or system crashes requiring manual intervention.
If Mitigated
Controlled crash or service interruption with no data corruption if proper segmentation and access controls are implemented.
🎯 Exploit Status
Proof of concept available in GitHub issues. Exploitation requires sending specially crafted IEC104 packets to the vulnerable parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version with proper bounds checking for Iec10x_Sta_Addr parameter
Vendor Advisory: https://github.com/airpig2011/IEC104/issues/14
Restart Required: Yes
Instructions:
1. Download patched version from repository. 2. Replace vulnerable IEC104 v1.0 installation. 3. Restart IEC104 service. 4. Verify proper bounds checking is implemented for Iec10x_Sta_Addr parameter.
🔧 Temporary Workarounds
Network Segmentation
allIsolate IEC104 systems from untrusted networks using firewalls and VLANs
Input Validation Rules
allImplement network filtering to validate Iec10x_Sta_Addr parameter values
🧯 If You Can't Patch
- Implement strict network access controls to limit connections to IEC104 systems
- Deploy intrusion detection systems to monitor for buffer overflow attempts
🔍 How to Verify
Check if Vulnerable:
Check if running IEC104 v1.0 and examine source code for lack of bounds checking on Iec10x_Sta_Addr parameterCheck Version:
Check IEC104 version in configuration files or via service status commandsVerify Fix Applied:
Test with malformed IEC104 packets containing oversized Iec10x_Sta_Addr values and verify system stability📡 Detection & Monitoring
Log Indicators:
- IEC104 service crashes
- Memory access violation errors
- Unusual parameter values in IEC104 logs
Network Indicators:
- IEC104 packets with abnormally large Iec10x_Sta_Addr values
- Multiple connection attempts with malformed packets
SIEM Query:
source="iec104" AND (event_type="crash" OR param_size>normal_threshold)