CVE-2021-22648
📋 TL;DR
This vulnerability in Ovarro TBox devices allows attackers to read, modify, or delete configuration files via Modbus file access functions. This affects industrial control systems using vulnerable TBox devices, potentially compromising operational technology environments.
💻 Affected Systems
- Ovarro TBox
📦 What is this software?
Twinsoft by Ovarro
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to alter critical configuration files, disrupt industrial processes, or maintain persistent access to operational technology networks.
Likely Case
Unauthorized access to configuration files leading to operational disruption, data theft, or manipulation of industrial control parameters.
If Mitigated
Limited impact with proper network segmentation and access controls preventing unauthorized Modbus access.
🎯 Exploit Status
Exploitation requires network access to Modbus port (typically 502). No authentication needed for Modbus protocol.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 2.3.0 and later
Vendor Advisory: https://www.cisa.gov/uscert/ics/advisories/icsa-21-054-04
Restart Required: Yes
Instructions:
1. Download TBox firmware version 2.3.0 or later from Ovarro. 2. Follow vendor's firmware update procedure. 3. Verify successful update and restart device.
🔧 Temporary Workarounds
Network Segmentation
allIsolate TBox devices from untrusted networks using firewalls and VLANs.
Disable Modbus if Unused
allDisable Modbus protocol on TBox devices if not required for operations.
🧯 If You Can't Patch
- Implement strict network access controls to limit Modbus traffic to authorized sources only.
- Monitor Modbus traffic for unauthorized access attempts and configuration file changes.
🔍 How to Verify
Check if Vulnerable:
Check TBox firmware version via web interface or serial console. Versions below 2.3.0 are vulnerable.Check Version:
Check via TBox web interface at System > About or via serial console connection.Verify Fix Applied:
Confirm firmware version is 2.3.0 or later and test Modbus file access functions are properly restricted.📡 Detection & Monitoring
Log Indicators:
- Unauthorized Modbus access attempts
- Configuration file modification events
Network Indicators:
- Unexpected Modbus traffic to port 502
- Modbus function codes 20/21/22 for file access
SIEM Query:
source_port:502 AND (function_code:20 OR function_code:21 OR function_code:22)