CVE-2021-47770
📋 TL;DR
OpenPLC v3 contains an authenticated remote code execution vulnerability that allows attackers with valid credentials to upload malicious hardware configuration files containing reverse shell code. This enables complete system compromise of the OpenPLC server. Any organization using OpenPLC v3 with exposed web interfaces is affected.
💻 Affected Systems
- OpenPLC v3
⚠️ 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 compromise of the OpenPLC server leading to industrial control system manipulation, lateral movement to OT networks, and potential physical damage to industrial processes.
Likely Case
Attackers with stolen or default credentials gain full control of the OpenPLC server, enabling data theft, process disruption, and persistence in industrial networks.
If Mitigated
With proper network segmentation and credential management, impact is limited to the OpenPLC server itself without affecting broader industrial control systems.
🎯 Exploit Status
Exploit requires valid credentials but is straightforward with public proof-of-concept available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check latest version from official repository
Vendor Advisory: https://github.com/thiagoralves/OpenPLC_v3
Restart Required: Yes
Instructions:
1. Update to latest OpenPLC v3 version from official repository. 2. Restart OpenPLC service. 3. Verify hardware configuration file validation is enabled.
🔧 Temporary Workarounds
Network Segmentation
allIsolate OpenPLC servers from internet and restrict access to authorized networks only.
Credential Hardening
allChange default credentials and implement strong password policies with multi-factor authentication if possible.
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach the OpenPLC web interface
- Monitor for unauthorized hardware configuration uploads and implement file integrity monitoring
🔍 How to Verify
Check if Vulnerable:
Check if OpenPLC v3 is running and accessible via web interface. Review version against latest patched release.Check Version:
Check OpenPLC web interface dashboard or service logs for version informationVerify Fix Applied:
Verify OpenPLC version is updated and test that hardware configuration file uploads are properly validated.📡 Detection & Monitoring
Log Indicators:
- Unauthorized hardware configuration uploads
- Suspicious file upload patterns to /hardware endpoint
- Reverse shell connection attempts from OpenPLC process
Network Indicators:
- Outbound connections from OpenPLC server to unknown IPs/ports
- Unusual network traffic patterns from OpenPLC interface
SIEM Query:
source="openplc.log" AND (event="hardware_upload" OR event="file_upload") AND status="success"