CVE-2025-20085 Overview
A denial of service vulnerability exists in the Modbus RTU over TCP functionality of Socomec DIRIS Digiware M-70 firmware version 1.6.9. This vulnerability stems from missing authentication for a critical function (CWE-306), allowing an attacker to send specially crafted network packets that can cause denial of service conditions and weaken device credentials. Upon successful exploitation, default documented credentials are applied to the device, potentially allowing unauthorized access. The attack requires no authentication, making it particularly dangerous for exposed industrial control systems.
Critical Impact
Unauthenticated attackers can remotely cause denial of service and force credential reset to default documented values, potentially compromising industrial power monitoring systems.
Affected Products
- Socomec DIRIS Digiware M-70 Firmware version 1.6.9
- Socomec DIRIS Digiware M-70 Hardware
Discovery Timeline
- December 1, 2025 - CVE-2025-20085 published to NVD
- December 5, 2025 - Last updated in NVD database
Technical Details for CVE-2025-20085
Vulnerability Analysis
CVE-2025-20085 is classified as a Missing Authentication for Critical Function vulnerability (CWE-306) affecting the Modbus RTU over TCP implementation in Socomec DIRIS Digiware M-70 power monitoring devices. The vulnerability carries a CVSS v3.1 score of 6.5 (Medium) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
The attack characteristics include:
- Attack Vector: Network-based
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: None
The EPSS (Exploit Prediction Scoring System) probability is 0.037%, placing it in the 10.49th percentile as of December 16, 2025, indicating a relatively low likelihood of exploitation in the wild.
Root Cause
The root cause of this vulnerability lies in the missing authentication mechanism for the Modbus RTU over TCP functionality. The DIRIS Digiware M-70 device fails to properly authenticate network requests to critical device functions, specifically those that can affect device configuration and credential management. This oversight allows any network-accessible attacker to interact with sensitive device functionality without providing valid credentials.
Industrial control devices like the DIRIS Digiware M-70 are commonly deployed in power monitoring and management scenarios. The absence of authentication on the Modbus RTU interface represents a significant design flaw, as Modbus protocol implementations in industrial environments often lack native security features and rely on network segmentation for protection.
Attack Vector
The attack is network-based and can be executed remotely by any attacker with network access to the vulnerable device. The attacker sends a specially crafted packet to the Modbus RTU over TCP service, which triggers the denial of service condition and resets device credentials to their default documented values.
The vulnerability mechanism operates as follows:
- The attacker identifies a Socomec DIRIS Digiware M-70 device accessible via network (typically on Modbus TCP port 502)
- A malicious network packet is crafted to target the vulnerable Modbus RTU over TCP functionality
- Upon processing the malicious packet, the device enters a denial of service state
- Device credentials are reset to default documented values
- The attacker can then authenticate using well-known default credentials
For detailed technical information about the exploitation mechanism, refer to the Cisco Talos vulnerability report at TALOS-2025-2138.
Detection Methods for CVE-2025-20085
Indicators of Compromise
- Unexpected authentication failures followed by successful logins using default credentials on DIRIS Digiware M-70 devices
- Unusual Modbus TCP traffic patterns or malformed packets targeting port 502
- Device configuration changes or resets without authorized administrator action
- Network traffic from unauthorized sources to Modbus RTU over TCP services
Detection Strategies
Organizations should implement network monitoring to detect exploitation attempts:
- Network Traffic Analysis: Monitor Modbus TCP traffic (default port 502) for anomalous packet structures or unusual communication patterns that don't match legitimate SCADA/HMI traffic
- Authentication Log Monitoring: Track authentication events on DIRIS Digiware M-70 devices, alerting on credential resets or logins using default credentials
- Device Configuration Monitoring: Implement configuration change detection to identify unauthorized modifications to device settings
- IDS/IPS Signatures: Deploy industrial protocol-aware intrusion detection systems capable of identifying malformed Modbus packets
SentinelOne Singularity™ platform provides comprehensive visibility into network-connected assets and can detect anomalous behavior patterns indicative of industrial control system attacks.
Monitoring Recommendations
- Implement network segmentation to isolate industrial control systems from general network traffic
- Deploy network monitoring solutions with Modbus protocol awareness
- Configure alerting for authentication events using default or documented credentials
- Establish baseline Modbus communication patterns and alert on deviations
- Monitor device availability and trigger alerts on unexpected restarts or service interruptions
- Review Cisco Talos report TALOS-2025-2138 for additional detection guidance
How to Mitigate CVE-2025-20085
Immediate Actions Required
- Restrict network access to DIRIS Digiware M-70 devices to authorized management stations only
- Implement firewall rules to block unauthorized access to Modbus TCP port 502
- Place vulnerable devices behind VPN or other secure remote access solutions
- Review and update device credentials immediately if default credentials are in use
- Monitor for security updates from Socomec and apply patches when available
Patch Information
Organizations should consult the official Socomec security advisory for firmware updates and remediation guidance:
- Vendor Security Advisory: Socomec CVE-2025-20085 Advisory (PDF)
- Cisco Talos Report: TALOS-2025-2138
Contact Socomec support for the latest firmware version that addresses this vulnerability and follow their recommended update procedures for industrial deployments.
Workarounds
If immediate patching is not possible, implement the following network-level mitigations:
# Example iptables rules to restrict Modbus TCP access
# Allow only authorized SCADA/HMI systems to communicate with DIRIS devices
# Replace 10.0.0.100 with your DIRIS M-70 device IP
# Replace 192.168.1.50 with your authorized SCADA/HMI system IP
iptables -A FORWARD -d 10.0.0.100 -p tcp --dport 502 -s 192.168.1.50 -j ACCEPT
iptables -A FORWARD -d 10.0.0.100 -p tcp --dport 502 -j DROP
# Log blocked connection attempts for monitoring
iptables -A FORWARD -d 10.0.0.100 -p tcp --dport 502 -j LOG --log-prefix "MODBUS_BLOCKED: "
Additional workarounds include:
- Deploy industrial-grade firewalls with deep packet inspection for Modbus protocols
- Implement network segmentation using VLANs to isolate OT networks from IT networks
- Use a VPN gateway for any remote management requirements
- Change default credentials immediately and enforce strong password policies
- Disable Modbus RTU over TCP functionality if not operationally required
- Implement physical access controls to limit local network access to industrial systems
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
