Checking Memory Size

Created the Monday 11 March 2019. Updated 6 months, 2 weeks ago.

Most modern user machines have at least 4GB of memory. Malware programs can detect whether they are running in a sandbox environment by checking the available memory size. If the available memory size is less than 4GB, it is likely that the program is running in a sandbox.

Technique Identifiers

U1313 B0009.014

Technique Tags

memory malware sandbox available memory size.

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.

GlobalMemoryStatusEx

Code Snippets

Description

This code uses the MEMORYSTATUSEX structure and the GlobalMemoryStatusEx function from the Windows API to retrieve information about the system's memory status, including the total physical memory and the available physical memory.

#include <windows.h>
#include <iostream>

int main() {
    MEMORYSTATUSEX memInfo;
    memInfo.dwLength = sizeof(MEMORYSTATUSEX);
    GlobalMemoryStatusEx(&memInfo);

    std::cout << "Total physical memory: " << memInfo.ullTotalPhys / 1024 / 1024 << " MB\n";
    std::cout << "Available physical memory: " << memInfo.ullAvailPhys / 1024 / 1024 << " MB\n";

    return 0;
}

package main

import (
	"unsafe"
	"syscall"
	"fmt"
)

var (
	kernel_32               = syscall.MustLoadDLL("kernel32.dll")
	globalMemoryStatusEx, _ = kernel_32.FindProc("GlobalMemoryStatusEx")
)

type memStatusEx struct {
	dwLength     uint32
	dwMemoryLoad uint32
	ullTotalPhys uint64
	unused       [6]uint64
}

func evadeSystemMemory() () {
	msx := &memStatusEx{dwLength: 64}
	r, _, _ := globalMemoryStatusEx.Call(uintptr(unsafe.Pointer(msx)))
	if r == 0 {
		fmt.Println("Error getting memory status")
	}

	var maxMemory float64 = 2.0
	var system_memory = float64(msx.ullTotalPhys/1024/1024) / 1024

	if system_memory <= maxMemory {
		fmt.Println("Sandbox detected")
	} else {
		fmt.Println("Sandbox not detected")
	}
}

func main() {
	evadeSystemMemory()
}

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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