CVE-2024-5000
📋 TL;DR
An unauthenticated remote attacker can send a malicious OPC UA request to CODESYS products, causing a denial-of-service (DoS) due to incorrect buffer size calculation. This affects CODESYS products using vulnerable OPC UA server components. The vulnerability allows disruption of industrial control systems without authentication.
💻 Affected Systems
- CODESYS products with OPC UA server functionality
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption of industrial control systems, halting production processes and causing operational downtime.
Likely Case
Temporary DoS affecting OPC UA communication, disrupting monitoring and control functions until service restart.
If Mitigated
Limited impact with proper network segmentation and monitoring, potentially causing brief service interruptions.
🎯 Exploit Status
Exploitation requires network access to OPC UA port (typically 4840/tcp). No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific patched versions
Vendor Advisory: https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=18355&token=e3e5a937ce72602bec39718ddc2f4ba6d983ccd1&download=
Restart Required: Yes
Instructions:
1. Download the patch from CODESYS customer portal. 2. Apply the patch according to vendor instructions. 3. Restart affected services. 4. Verify OPC UA functionality post-patch.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to OPC UA port (4840/tcp) to trusted networks only.
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="TRUSTED_NETWORK" port port="4840" protocol="tcp" accept'
netsh advfirewall firewall add rule name="Restrict OPC UA" dir=in action=allow protocol=TCP localport=4840 remoteip=TRUSTED_NETWORK
Disable OPC UA Server
allTemporarily disable OPC UA server if not required for operations.
systemctl stop codesys-opcua
sc stop "CODESYS OPC UA Server"
🧯 If You Can't Patch
- Implement strict network access controls to OPC UA port (4840/tcp) using firewalls.
- Deploy intrusion detection systems to monitor for malicious OPC UA traffic patterns.
🔍 How to Verify
Check if Vulnerable:
Check CODESYS version against vendor advisory. Verify OPC UA server is running and accessible.Check Version:
codesyscontrol --version or check CODESYS runtime version in management interfaceVerify Fix Applied:
After patching, verify version is updated and test OPC UA functionality with legitimate clients.📡 Detection & Monitoring
Log Indicators:
- Unusual OPC UA connection attempts
- OPC UA server crash logs
- Buffer overflow errors in system logs
Network Indicators:
- Malformed OPC UA packets to port 4840
- Unusual traffic patterns to OPC UA port
SIEM Query:
source="firewall" dest_port=4840 AND (packet_size>threshold OR protocol_violation)🔗 References
- https://cert.vde.com/en/advisories/VDE-2024-026
- https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=18355&token=e3e5a937ce72602bec39718ddc2f4ba6d983ccd1&download=
- https://cert.vde.com/en/advisories/VDE-2024-026
- https://customers.codesys.com/index.php?eID=dumpFile&t=f&f=18355&token=e3e5a937ce72602bec39718ddc2f4ba6d983ccd1&download=
