Checking Hard Drive Size

Created the Monday 11 March 2019. Updated 6 months, 1 week ago.

Many user machines have hard drives that are larger than 80GB. A malware program can detect whether it is running in a virtual environment by checking the size of the hard drive. If the size is less than 80GB, it is likely that the program is running in a sandbox or virtual environment.

Technique Identifiers

U1312 B0009.015

Technique Tags

user machines hard drives size 80GB malware virtual environment sandbox

Featured Windows API's

Below, you will find a list of the most commonly used Windows API's that are currently utilized by malware authors for current evasion technique. This list is meant to provide an overview of the API's that are commonly used for this purpose. If there are any API's that you feel should be included on this list, please do not hesitate to contact us. We will be happy to update the list and provide any additional information or documentation that may be helpful.

GetDiskFreeSpaceExW

Code Snippets

Description

Python snippet to detect the drive size with GetDiskFreeSpaceExW

import ctypes
import math

# Convert octets
def convert_size(size_bytes):
    if size_bytes == 0:
        return "0B"
    size_name = ("B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
    i = int(math.floor(math.log(size_bytes, 1024)))
    p = math.pow(1024, i)
    s = round(size_bytes / p, 2)
    return "%s %s" % (s, size_name[i])


# Get disk size with API GetDiskFreeSpaceExW
def disk_size(path):
    PULARGE_INTEGER = ctypes.POINTER(ctypes.c_ulonglong)
    kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)
    kernel32.GetDiskFreeSpaceExW.argtypes = (ctypes.c_wchar_p,) + (PULARGE_INTEGER,) * 3

    _, total, free = ctypes.c_ulonglong(), ctypes.c_ulonglong(), ctypes.c_ulonglong()
    success = kernel32.GetDiskFreeSpaceExW(path, ctypes.byref(_), ctypes.byref(total), ctypes.byref(free))
    size = convert_size(total.value)
    print "The size of the disk is: ", size


if __name__ == '__main__':
    disk_size("C:/")

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

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