T1106: Native API

Adversaries may directly interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations.

Functionality provided by native APIs are often also exposed to user-mode applications via interfaces and libraries. For example, functions such as the Windows API CreateProcess() or GNU fork() will allow programs and scripts to start other processes. This may allow API callers to execute a binary, run a CLI command, load modules, etc. as thousands of similar API functions exist for various system operations.

Higher level software frameworks, such as Microsoft .NET and macOS Cocoa, are also available to interact with native APIs. These framework typically provide language wrappers/abstractions to API functionalities and are designed for ease-of-use/portability of code.

Adversaries may abuse these native API functions as a means of executing behaviors. Similar to Command and Scripting Interpreter, the native API and its hierarchy of interfaces, provide mechanisms to interact with and utilize various components of a victimized system.

In the following example will utilize the CreateProcess API which the documentation specifies that this API: Creates a new process and its primary thread. The new process runs in the security context of the calling process.

#include <iostream>
#include <Windows.h>

int main()
{

/*
 BOOL CreateProcessW(
  [in, optional]      LPCWSTR               lpApplicationName,
  [in, out, optional] LPWSTR                lpCommandLine,
  [in, optional]      LPSECURITY_ATTRIBUTES lpProcessAttributes,
  [in, optional]      LPSECURITY_ATTRIBUTES lpThreadAttributes,
  [in]                BOOL                  bInheritHandles,
  [in]                DWORD                 dwCreationFlags,
  [in, optional]      LPVOID                lpEnvironment,
  [in, optional]      LPCWSTR               lpCurrentDirectory,
  [in]                LPSTARTUPINFOW        lpStartupInfo,
  [out]               LPPROCESS_INFORMATION lpProcessInformation
);
*/

	STARTUPINFO si{ sizeof(si) };
	PROCESS_INFORMATION pi;

	wchar_t cmd[] = L"notepad.exe";
	BOOL ok = CreateProcessW(NULL,cmd, NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);
}