Thermal Zone Temperature

The temperature sensor is used to know the current temperature of a machine. In a non-virtualized environment, the function returns valid support and output like: “25.05 C: 77.09 F: 298.2K”. But for a fully virtualized environment, the return is “MSAcpi_ThermalZoneTemperature not supported” because this feature is not supported on virtualized processors.

Interestingly, this method is not valid. Not all Windows machines will support this method due to incompatibility with thermal zone sensors. It is a BIOS function. Sometimes the BIOS manufacturer provides dlls that can be referenced to call the required function and return the details.

Many malware authors use it to detect virtual machines, but it frequently fails due to lack of vendor support.

U1302

Code Snippets

Glacius

Description

If the return is “MSAcpi_ThermalZoneTemperature not supported, it means you are in a virtualized environment.
Reference : https://gist.github.com/teixeira0xfffff/36293713c254c69a7ba2353e8d64afce#file-msacpi_thermalzonetemperature-ps1

function Get-AntiVMwithTemperature {
    $t = Get-WmiObject MSAcpi_ThermalZoneTemperature -Namespace "root/wmi"
    $valorTempKelvin = $t.CurrentTemperature / 10
    $valorTempCelsius = $valorTempKelvin - 273.15
    $valorTempFahrenheit = (9/5) * $valorTempCelsius + 32
    return $valorTempCelsius.ToString() + " C : " + $valorTempFahrenheit.ToString() + " F : " + $valorTempKelvin + "K"  
}

Detection Rules

rule Detect_AntiVMWithTemperature {
    meta:
        description = "Rue to detect AntiVMwithTemperature technique"
        author = "Thibault Seret"
        date = "2020-09-26"
    strings:
        $s1 = {72 6f 6f 74 5c 57 4d 49}
        // root\WMI
        $s2 = {53 45 4c 45 43 54 20 2a 20 46 52 4f 4d 20 4d 53 41 63 70 69 5f 54 68 65 72 6d 61 6c 5a 6f 6e 65 54 65 6d 70 65 72 61 74 75 72 65}
        // SELECT * FROM MSAcpi_ThermalZoneTemperature
        $s3 = {43 75 72 72 65 6e 74 54 65 6d 70 65 72 61 74 75 72 65}
        //  CurrentTemperature
    
    condition:
    all of them

Additional Resources

Subscribe to our Newsletter


The information entered into this form is mandatory. It will be subjected to computer processing. It is processed by computer in order to support our users and readers. The recipients of the data will be : contact@unprotect.it.

According to the Data Protection Act of January 6th, 1978, you have at any time, a right of access to and rectification of all of your personal data. If you wish to exercise this right and gain access to your personal data, please write to Thomas Roccia at contact@unprotect.it.

You may also oppose, for legitimate reasons, the processing of your personal data.