Socomec DIRIS M-70 Gateway: Six Critical DoS Vulnerabilities Exposed

Cisco Talos researchers discovered six high-severity denial-of-service vulnerabilities in Socomec DIRIS M-70 IIoT gateways. The flaws affect firmware version 1.6.9 and enable remote attackers to crash devices via specially crafted Modbus messages. No authentication required for exploitation.

The DIRIS M-70 monitors power quality in data centers, hospitals, and industrial facilities. It handles Modbus RTU/TCP, BACnet IP, and SNMP over RS485/Ethernet. CVSS v3.1 scores range from 7.5 across all six flaws tracked as CVE-2025-54848 through CVE-2025-55222.

Researchers bypassed hardware debug protection using selective thread emulation. Full system emulation proved impractical due to STM32 microcontroller RDP Level 1 restrictions.

Traditional JTAG debugging failed against Code Readout Protection. Talos extracted unencrypted firmware for analysis. They emulated only the Modbus processing thread using Unicorn Engine, then applied AFL fuzzing.

Over 700 Modbus message types made manual testing impossible. Fuzzing revealed buffer overflows and parsing errors triggering device reboots. Qiling framework later added coverage visualization.

Vulnerability Details Table

CVE ID	CVSS Score	Attack Vector	Impact
CVE-2025-54848	7.5	Network	Device reboot
CVE-2025-54849	7.5	Network	Modbus parser crash
CVE-2025-54850	7.5	Network	Memory corruption
CVE-2025-54851	7.5	Network	Stack overflow
CVE-2025-55221	7.5	Network	Service disruption
CVE-2025-55222	7.5	Network	Infinite loop

All vulnerabilities require low complexity. No privileges or user interaction needed.

Emulation Methodology

Hardware limitations overcome:

• RDP Level 1 blocked JTAG flash reads
• Full ARM emulation too resource intensive
• 700+ Modbus handlers impractical manually

Selective thread approach:

1. Extract firmware → Identify Modbus thread
2. Unicorn Engine → Single thread execution  
3. AFL fuzzing → Coverage-guided inputs
4. Qiling framework → Debug + visualization

This technique cut development time dramatically while achieving full vulnerability coverage.

Technical Discovery Process

Firmware analysis revealed Modbus thread isolation feasibility. Unicorn executed specific handlers without OS dependencies. AFL generated malformed Modbus TCP/RTU-over-TCP packets.

Crash analysis confirmed remote exploitability:

Modbus function code parsing flaws
Buffer boundary violations
Integer overflow conditions
State machine corruption

Each flaw independently crashes the gateway. Attackers chain multiple for persistent disruption.

Affected Device Profile

DIRIS M-70 deployment:

• Power monitoring gateways
• RS485/Ethernet industrial comms
• Data centers, hospitals, factories
• Firmware 1.6.9 vulnerable

Attack surface:

Internet-facing management ports
Internal industrial networks
Remote SCADA access points

Impact Assessment

Operational consequences:

• Power monitoring blackout
• Energy management failure
• Equipment protection loss
• Safety system blind spots

Critical infrastructure risk:

Data center UPS monitoring offline
Hospital backup power tracking down
Manufacturing line power quality blind

CVSS Attack Vector: Network across all flaws.

Vendor Response Status

Socomec patches:

• Firmware 1.6.9 → 1.7+ resolves all issues
• Coordinated disclosure via Cisco policy
• Update immediately recommended

Detection rules:

SNORT signatures available: snort.org
Modbus anomaly detection
Traffic pattern analysis

Immediate Mitigation Steps

Network controls:

• Restrict Modbus TCP/RTU ports
• IP whitelist management access
• VLAN isolate IIoT devices
• OT network segmentation

Firmware management:

1. Backup current config
2. Download 1.7+ from Socomec
3. Verify update integrity
4. Apply during maintenance window

Detection Signatures

Network indicators:

Modbus malformed function codes
Excessive TCP RST from gateway
RS485 traffic spikes pre-crash
Port 502 anomalies

Device symptoms:

Intermittent reboots every 5-15min
Modbus timeout errors
Web interface unresponsive
SNMP polling failures

Research Innovation Value

Selective thread emulation proves superior for IIoT vulnerability discovery. Bypasses hardware protections while minimizing emulation complexity. AFL+Qiling combination accelerates fuzzing-debug cycles.

Key takeaways:

• Single-thread focus beats full emulation
• Firmware extraction essential
• Coverage-guided fuzzing scales to 700+ handlers
• RDP Level 1 no longer absolute barrier

Risk Prioritization

Exposure	Priority	Action
Internet-facing	Critical	Firmware + firewall NOW
DMZ/SCADA	High	Firmware update + segment
Internal plant	Medium	Scheduled patching
Air-gapped	Low	Monitor vendor advisories

FAQ