DMI Decoder configurations

This article explains how to configure the DMI decoder, and alternative configurations for devices that do not support it.

Note

Defender for IoT plans to retire the micro agent on June 1, 2027.

Overview

The Microsoft Defender for IoT Device inventory provides an overview of all IoT devices in your environment. The device inventory table can be customized to your preferences by adding or removing information fields, and filtering the fields.

The DMI decoder is used to retrieve data on the hardware and firmware of the device.

Retrieved fields are:

  • Firmware vendor
  • Firmware version
  • Hardware model
  • Hardware serial number
  • Hardware vendor

For more information on the DMI Decoder, see dmidecode(8): DMI table decoder - Linux man page (die.net).

Populate SMBIOS tables for dmidecode

The dmidecode(8) utility reads System Management BIOS (SMBIOS) tables to extract hardware and firmware information from the device. To support dmidecode(8), SMBIOS tables need to be present and valid. To implement SMBIOS support for dmidecode(8), refer to the System Management BIOS specifications.

Choose an alternative configuration method

For devices that do not support the DMI decoder, there are two alternative options for retrieving and setting the firmware and hardware fields:

Configure DMI Decoder by using a JSON file

To manually set the values on the device, create a JSON file. The micro agent will read the values from the JSON file and send them to the cloud.

To configure the file, use the following path and format details:

  • Path:

        /etc/defender_iot_micro_agent/sysinfo.json

  • Format:

        "HardwareVendor": "<hardware vendor>", 
    "HardwareModel": "<hardware model>",
    "HardwareSerialNumber": "<hardware serial number>", 
    "FirmwareVendor": "<firmware vendor>", 
    "FirmwareVersion": "<firmware version>"

Configure DMI Decoder by using module twin settings

To manually set the values on the cloud, use the module twin configuration. Set the following desired properties in the module twin JSON payload:

{
  "properties": {
    "desired": {
      "SystemInformation_HardwareVendor": "<data>",
      "SystemInformation_HardwareModel": "<data>",
      "SystemInformation_FirmwareVendor": "<data>",
      "SystemInformation_FirmwareVersion": "<data>",
      "SystemInformation_HardwareSerialNumber": "<data>"
    }
  }
}

Related content

  • Last updated on