CVE-2025-55222 Overview
A denial of service vulnerability exists in the Modbus TCP and Modbus RTU over TCP USB Function functionality of Socomec DIRIS Digiware M-70 firmware version 1.6.9. This vulnerability allows an unauthenticated remote attacker to send specially crafted network packets that trigger a denial of service condition on the affected industrial device. The vulnerability is classified under CWE-306 (Missing Authentication for Critical Function), indicating that the Modbus protocol implementation lacks proper authentication controls.
This vulnerability specifically targets the Modbus RTU over TCP communication on port 503, a protocol commonly used in industrial control systems (ICS) and operational technology (OT) environments. The ability to disrupt power monitoring and metering equipment like the DIRIS Digiware M-70 without authentication poses significant risks to critical infrastructure.
Critical Impact
An unauthenticated remote attacker can cause denial of service on industrial power monitoring equipment via malicious Modbus RTU over TCP packets on port 503, potentially disrupting critical infrastructure monitoring capabilities.
Affected Products
- Socomec DIRIS M-70 Firmware version 1.6.9
- Socomec DIRIS M-70 Hardware
Discovery Timeline
- 2025-12-01 - CVE-2025-55222 published to NVD
- 2025-12-05 - Last updated in NVD database
Technical Details for CVE-2025-55222
Vulnerability Analysis
This vulnerability carries a CVSS 3.1 score of 7.5 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. The scoring breakdown indicates:
| Metric | Value | Description |
|---|---|---|
| Attack Vector | Network | Exploitable remotely over the network |
| Attack Complexity | Low | No special conditions required |
| Privileges Required | None | No authentication needed |
| User Interaction | None | No user action required |
| Scope | Unchanged | Impact limited to vulnerable component |
| Confidentiality | None | No data disclosure |
| Integrity | None | No data modification |
| Availability | High | Complete denial of service |
The EPSS (Exploit Prediction Scoring System) data shows a probability score of 0.057% with a percentile ranking of 17.754, indicating a relatively low likelihood of exploitation in the wild at this time.
Root Cause
The root cause of this vulnerability is CWE-306: Missing Authentication for Critical Function. The Modbus RTU over TCP implementation on port 503 does not implement proper authentication mechanisms before processing incoming packets. This allows any network-accessible attacker to send malicious Modbus messages directly to the device without credential verification.
Industrial protocols like Modbus were originally designed for closed, trusted networks and often lack built-in security features such as authentication and encryption. When these devices are deployed in network-accessible environments without additional security controls, they become vulnerable to exploitation.
Attack Vector
The attack leverages the network-accessible Modbus RTU over TCP service running on port 503 of the Socomec DIRIS Digiware M-70 device. An attacker with network connectivity to the target device can craft malicious Modbus RTU packets that, when processed by the vulnerable firmware, cause the device to enter a denial of service state.
The attack requires no authentication, no special privileges, and no user interaction. The attacker simply needs to send a specially crafted network packet to port 503 where the Modbus RTU over TCP service is listening. The vulnerability appears to be triggered by malformed or unexpected data within the Modbus RTU protocol frames that the firmware fails to handle gracefully.
For technical details on the specific exploitation mechanism, refer to the Cisco Talos security advisory at TALOS-2025-2251.
Detection Methods for CVE-2025-55222
Indicators of Compromise
- Unexpected network traffic targeting port 503 (Modbus RTU over TCP) from unauthorized sources
- Device availability issues or unresponsive behavior of DIRIS Digiware M-70 units
- Anomalous Modbus RTU packet patterns in network traffic captures
- Multiple failed communication attempts to power monitoring equipment
- Device reboots or service restarts without scheduled maintenance
Detection Strategies
Network Traffic Analysis:
Monitor for unusual traffic patterns on port 503, particularly from external or unauthorized source IP addresses. Implement deep packet inspection (DPI) for Modbus RTU over TCP traffic to identify malformed or suspicious protocol messages.
ICS/SCADA Monitoring:
Deploy industrial control system (ICS) specific monitoring solutions that understand Modbus protocol semantics and can identify protocol anomalies or abuse patterns.
Endpoint Detection:
SentinelOne Singularity platform provides comprehensive visibility into network communications and can detect anomalous traffic patterns targeting industrial protocols. The platform's behavioral AI can identify denial of service attack patterns and alert security teams to potential exploitation attempts.
Monitoring Recommendations
Organizations should implement the following monitoring controls:
- Network Segmentation Monitoring - Alert on any traffic crossing network boundaries to reach industrial devices on port 503
- Availability Monitoring - Implement heartbeat/health checks for DIRIS Digiware M-70 devices to detect service disruptions
- Traffic Baseline Analysis - Establish normal Modbus communication patterns and alert on deviations
- Asset Inventory - Maintain accurate inventory of all Socomec devices running firmware version 1.6.9
How to Mitigate CVE-2025-55222
Immediate Actions Required
- Identify all Socomec DIRIS Digiware M-70 devices running firmware version 1.6.9 in your environment
- Implement network segmentation to isolate affected devices from untrusted networks
- Deploy firewall rules to restrict access to port 503 from authorized management stations only
- Monitor Cisco Talos and Socomec advisories for firmware updates that address this vulnerability
- Consider deploying an industrial firewall or intrusion prevention system (IPS) in front of affected devices
Patch Information
Organizations should consult the official Cisco Talos vulnerability report at TALOS-2025-2251 for the latest patch information and firmware updates from Socomec. Contact Socomec support directly for guidance on obtaining and applying security updates for the DIRIS Digiware M-70 product line.
Verify any firmware updates are tested in a non-production environment before deployment to critical systems, and ensure proper change management procedures are followed when updating industrial equipment.
Workarounds
If immediate patching is not possible, implement the following compensating controls:
Network Access Control:
Restrict network access to port 503 on affected devices using firewall rules or access control lists (ACLs). Only allow connections from authorized management stations and monitoring systems.
# Example iptables rules to restrict Modbus RTU over TCP access
# Allow only authorized management station (example IP: 192.168.1.100)
iptables -A INPUT -p tcp --dport 503 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 503 -j DROP
# Log blocked connection attempts for monitoring
iptables -A INPUT -p tcp --dport 503 -j LOG --log-prefix "MODBUS_BLOCKED: "
Network Segmentation:
Place DIRIS Digiware M-70 devices on isolated network segments with strict ingress/egress controls. Implement jump servers or bastion hosts for administrative access to these devices.
VPN or Encrypted Tunnels:
If remote access to Modbus services is required, implement VPN tunnels or encrypted overlays to provide authentication and confidentiality for protocol traffic.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
