CVE-2021-30186
📋 TL;DR
CVE-2021-30186 is a heap-based buffer overflow vulnerability in CODESYS V2 runtime system SP. This vulnerability allows attackers to execute arbitrary code or cause denial of service by sending specially crafted requests. Organizations using CODESYS V2 runtime system SP for industrial control systems are affected.
💻 Affected Systems
- CODESYS V2 runtime system SP
📦 What is this software?
Plcwinnt by Codesys
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, manipulation of industrial processes, or permanent system damage.
Likely Case
Denial of service causing PLC/programmable logic controller disruption and industrial process downtime.
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts.
🎯 Exploit Status
Heap-based buffer overflows typically require specific knowledge of memory layout but can be exploited remotely without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.4.7.55 or later
Vendor Advisory: https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=14725&token=08691519ef764b252630759eff925890176ecd78&download=
Restart Required: Yes
Instructions:
1. Download patch from CODESYS customer portal. 2. Backup current configuration. 3. Install update following vendor instructions. 4. Restart affected systems. 5. Verify version update.
🔧 Temporary Workarounds
Network Segmentation
allIsolate CODESYS systems from untrusted networks and internet
Access Control Restrictions
allImplement strict firewall rules to limit access to CODESYS ports
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected systems
- Deploy intrusion detection systems monitoring for buffer overflow attempts
🔍 How to Verify
Check if Vulnerable:
Check CODESYS runtime version via CODESYS development environment or system propertiesCheck Version:
Check via CODESYS IDE: Project → Target Settings → Device → VersionVerify Fix Applied:
Verify version is 2.4.7.55 or higher in CODESYS development environment📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes
- Memory access violations
- Abnormal network traffic to CODESYS ports
Network Indicators:
- Unusual traffic patterns to CODESYS ports (typically 1217, 2455)
- Malformed packets targeting CODESYS services
SIEM Query:
source="codesys" AND (event_type="crash" OR event_type="memory_violation")🔗 References
- https://customers.codesys.com/index.php
- https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=14725&token=08691519ef764b252630759eff925890176ecd78&download=
- https://customers.codesys.com/index.php
- https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=14725&token=08691519ef764b252630759eff925890176ecd78&download=
