The Socomec DIRIS Digiware M-70 is a gateway used for centralizing the monitoring and measurement of electrical installations. These devices are critical components in operational technology (OT) environments, such as industrial plants, data centers, and other critical infrastructure, providing essential visibility into energy consumption and power quality.

A high-risk vulnerability has been identified that allows an unauthenticated attacker on the network to cause a complete Denial of Service (DoS), rendering the device unresponsive. The primary risk is operational disruption: an attack could obscure critical power supply events, mask other malicious activities, or hinder facility management, resulting in costly downtime.

This vulnerability is not currently listed in CISA’s KEV (Known Exploited Vulnerabilities) catalog, and there are no public reports of active exploitation. However, the attack is simple to execute, requiring only a single specially crafted network packet, lowering the barrier for malicious actors intending to develop and deploy an exploit. Any M-70 gateway with the Modbus TCP port accessible is at risk.

Technical Summary

The vulnerability resides in the Modbus TCP stack of the Socomec DIRIS Digiware M-70 gateway. The root cause is improper handling of malformed packets sent to the Modbus service, a common issue classified as CWE-20: Improper Input Validation. The device does not correctly validate the structure of an incoming packet before processing it, leading to a state that causes the service—and subsequently the entire device—to crash.

The attack unfolds as follows:

1. An attacker identifies a DIRIS Digiware M-70 device with the Modbus TCP port (typically 502/TCP) accessible on the network.
2. The attacker creates a single malicious Modbus TCP packet designed to exploit the parsing vulnerability in the device’s firmware.
3. Upon receiving and processing the malformed packet, the firmware enters an irreversible error state, causing a total denial of service. The gateway ceases all monitoring and communication functions until it is manually restarted.

• Affected Version: Firmware version 1.6.9 is confirmed to be vulnerable.
• Fix Availability: No specific fixed version has been announced. Users should contact the vendor for guidance and firmware updates.

An unauthenticated remote attacker can interrupt power monitoring operations, effectively creating a “loss of visibility” scenario for critical infrastructure operators.

// Conceptual Logic of the Flaw
// The device's Modbus TCP handler lacks robust error checking.
void modbus_tcp_handler(Packet* packet) {
    // A malformed packet might specify an invalid data length or function code.
    int data_length = packet->get_length();

    // VULNERABILITY: No check to see if 'data_length' is within a valid range.
    // An attacker can provide a value that causes a crash when the buffer
    // is processed based on this faulty length.
    process_buffer(packet->data, data_length); // This call triggers the crash.
}

Recommendations

• Update immediately: Contact Socomec to obtain information on firmware updates that resolve CVE-2024-48882 and apply them as soon as they become available.
• Mitigations:
  • Restrict network access to the Modbus TCP service (port 502) on DIRIS Digiware M-70 gateways.
  • Implement strict network segmentation to ensure that OT devices like the M-70 are not accessible from the internet or untrusted corporate networks. Access should be limited to a dedicated, trusted management network.
  • Use firewall access control lists (ACLs) or similar solutions to enforce the principle of least privilege, allowing only authorized systems to communicate with the device.

• Research and Monitoring:
  • Monitor network logs for unexpected or anomalous traffic directed at port 502/TCP on sensitive OT assets.
  • Monitor connection attempts originating from unauthorized IP ranges or subnets.
  • Set up alerts in asset management systems to detect when a DIRIS Digiware M-70 gateway becomes unresponsive or requires an unplanned restart.

• Incident Response:
  • If a device is found to be unresponsive, isolate it from the network immediately to prevent further interaction.
  • Perform a controlled power cycle to restore functionality.
  • Before reconnecting the device, ensure that mitigating network controls are in place to block the attack vector.

• Defense in Depth:
  • Maintain a complete and up-to-date inventory of all OT/ICS assets and their respective firmware versions.
  • Develop and test an incident response plan that specifically addresses operational technology environments.

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