Native API

Adversaries may directly interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes.[1][2] 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.[3][4] 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.[5][6][7]

Higher level software frameworks, such as Microsoft .NET and macOS Cocoa, are also available to interact with native APIs. These frameworks typically provide language wrappers/abstractions to API functionalities and are designed for ease-of-use/portability of code.[8][9][10][11]

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.

ID: T1106
Sub-techniques:  No sub-techniques
Tactic: Execution
Platforms: Linux, Windows, macOS
Permissions Required: User
Data Sources: Module: Module Load, Process: OS API Execution
Contributors: Stefan Kanthak
Version: 2.0
Created: 31 May 2017
Last Modified: 01 July 2020

Procedure Examples

ID Name Description
S0045 ADVSTORESHELL

ADVSTORESHELL is capable of starting a process using CreateProcess.[12]

G0067 APT37

APT37 leverages the Windows API calls: VirtualAlloc(), WriteProcessMemory(), and CreateRemoteThread() for process injection.[13]

S0456 Aria-body

Aria-body has the ability to launch files using ShellExecute.[14]

S0438 Attor

Attor's dispatcher has used CreateProcessW API for execution.[15]

S0475 BackConfig

BackConfig can leverage API functions such as ShellExecuteA and HttpOpenRequestA in the process of downloading and executing files.[16]

S0128 BADNEWS

BADNEWS has a command to download an .exe and execute it via CreateProcess API. It can also run with ShellExecute.[17][18]

S0239 Bankshot

Bankshot creates processes using the Windows API calls: CreateProcessA() and CreateProcessAsUserA().[19]

S0534 Bazar

Bazar can use various APIs to allocate memory and facilitate code execution/injection.[20]

S0470 BBK

BBK has the ability to use the CreatePipe API to add a sub-process for execution via cmd.[21]

S0574 BendyBear

BendyBear can load and execute modules and Windows Application Programming (API) calls using standard shellcode API hashing.[22]

S0570 BitPaymer

BitPaymer has used dynamic API resolution to avoid identifiable strings within the binary, including RegEnumKeyW.[23]

S0521 BloodHound

BloodHound can use .NET API calls in the SharpHound ingestor component to pull Active Directory data.[24]

S0471 build_downer

build_downer has the ability to use the WinExec API to execute malware on a compromised host.[21]

S0484 Carberp

Carberp has used the NtQueryDirectoryFile and ZwQueryDirectoryFile functions to hide files and directories.[25]

G0114 Chimera

Chimera has used direct Windows system calls by leveraging Dumpert.[26]

S0154 Cobalt Strike

Cobalt Strike's "beacon" payload is capable of running shell commands without cmd.exe and PowerShell commands without powershell.exe[27][28]

S0126 ComRAT

ComRAT can load a PE file from memory or the file system and execute it with CreateProcessW.[29]

S0575 Conti

Conti has used API calls during execution.[30][31]

S0354 Denis

Denis used the IsDebuggerPresent, OutputDebugString, and SetLastError APIs to avoid debugging. Denis used GetProcAddress and LoadLibrary to dynamically resolve APIs. Denis also used the Wow64SetThreadContext API as part of a process hollowing process.[32]

S0554 Egregor

Egregor has used the Windows API to make detection more difficult.[33]

S0363 Empire

Empire contains a variety of enumeration modules that have an option to use API calls to carry out tasks.[34]

S0396 EvilBunny

EvilBunny has used various API calls as part of its checks to see if the malware is running in a sandbox.[35]

S0569 Explosive

Explosive has a function to call the OpenClipboard wrapper.[36]

S0512 FatDuke

FatDuke can call ShellExecuteW to open the default browser on the URL localhost.[37]

G0047 Gamaredon Group

Gamaredon Group malware has used CreateProcess to launch additional malicious components.[38]

S0032 gh0st RAT

gh0st RAT has used the InterlockedExchange, SeShutdownPrivilege, and ExitWindowsEx Windows API functions.[39]

S0493 GoldenSpy

GoldenSpy can execute remote commands in the Windows command shell using the WinExec() API.[40]

S0477 Goopy

Goopy has the ability to enumerate the infected system's user name via GetUserNameW.[32]

G0078 Gorgon Group

Gorgon Group malware can leverage the Windows API call, CreateProcessA(), for execution.[41]

S0531 Grandoreiro

Grandoreiro can execute through the WinExec API.[42]

S0499 Hancitor

Hancitor has used CallWindowProc and EnumResourceTypesA to interpret and execute shellcode.[43]

S0391 HAWKBALL

HAWKBALL has leveraged several Windows API calls to create processes, gather disk information, and detect debugger activity.[44]

G0126 Higaisa

Higaisa has called various native OS APIs.[45]

S0431 HotCroissant

HotCroissant can perform dynamic DLL importing and API lookups using LoadLibrary and GetProcAddress on obfuscated strings.[46]

S0398 HyperBro

HyperBro has the ability to run an application (CreateProcessW) or script/file (ShellExecuteW) via API.[47]

S0537 HyperStack

HyperStack can use Windows API's ConnectNamedPipe and WNetAddConnection2 to detect incoming connections and connect to remote shares.[48]

S0483 IcedID

IcedID has called ZwWriteVirtualMemory, ZwProtectVirtualMemory, ZwQueueApcThread, and NtResumeThread to inject itself into a remote process.[49]

S0434 Imminent Monitor

Imminent Monitor has leveraged CreateProcessW() call to execute the debugger.[50]

S0259 InnaputRAT

InnaputRAT uses the API call ShellExecuteW for execution.[51]

S0260 InvisiMole

InvisiMole can use winapiexec tool for indirect execution of ShellExecuteW and CreateProcessA.[52]

S0395 LightNeuron

LightNeuron is capable of starting a process using CreateProcess.[53]

S0449 Maze

Maze has used several Windows API functions throughout the encryption process including IsDebuggerPresent, TerminateProcess, Process32FirstW, among others.[54]

S0576 MegaCortex

After escalating privileges, MegaCortex calls TerminateProcess(), CreateRemoteThread, and other Win32 APIs.[55]

G0045 menuPass

menuPass has used native APIs including GetModuleFileName, lstrcat, CreateFile, and ReadFile.[56]

S0455 Metamorfo

Metamorfo has used native WINAPI calls.[57][58]

S0256 Mosquito

Mosquito leverages the CreateProcess() and LoadLibrary() calls to execute files with the .dll and .exe extensions.[59]

S0457 Netwalker

Netwalker can use Windows API functions to inject the ransomware DLL.[60]

S0198 NETWIRE

NETWIRE can use Native API including CreateProcess GetProcessById, and WriteProcessMemory.[61]

S0385 njRAT

njRAT has used the ShellExecute() function within a script.[62]

G0116 Operation Wocao

Operation Wocao has used the CreateProcessA and ShellExecute API function to launch commands after being injected into a selected process.[63]

S0517 Pillowmint

Pillowmint has used multiple native Windows APIs to execute and conduct process injections.[64]

S0501 PipeMon

PipeMon's first stage has been executed by a call to CreateProcess with the decryption password in an argument. PipeMon has used a call to LoadLibrary to load its installer.[65]

S0013 PlugX

PlugX can use the Windows API function CreateProcess to execute another process.[66]

S0518 PolyglotDuke

PolyglotDuke can use LoadLibraryW and CreateProcess to load and execute code.[37]

S0453 Pony

Pony has used several Windows functions for various purposes.[67]

S0458 Ramsay

Ramsay can use Windows API functions such as WriteFile, CloseHandle, and GetCurrentHwProfile during its collection and file storage operations. Ramsay can execute its embedded components via CreateProcessA and ShellExecute.[68]

S0416 RDFSNIFFER

RDFSNIFFER has used several Win32 API functions to interact with the victim machine.[69]

S0496 REvil

REvil can use Native API for execution and to retrieve active services.[70][71]

S0448 Rising Sun

Rising Sun used dynamic API resolutions to various Windows APIs by leveraging LoadLibrary() and GetProcAddress().[72]

S0148 RTM

RTM can use the FindNextUrlCacheEntryA and FindFirstUrlCacheEntryA functions to search for specific strings within browser history.[73]

S0446 Ryuk

Ryuk has used multiple native APIs including ShellExecuteW to run executables,GetWindowsDirectoryW to create folders, and VirtualAlloc, WriteProcessMemory, and CreateRemoteThread for process injection.[74]

G0104 Sharpshooter

Sharpshooter's first-stage downloader resolved various Windows libraries and APIs, including LoadLibraryA(), GetProcAddress(), and CreateProcessA().[72]

S0444 ShimRat

ShimRat has used Windows API functions to install the service and shim.[75]

S0445 ShimRatReporter

ShimRatReporter used several Windows API functions to gather information from the infected system.[75]

G0091 Silence

Silence has leveraged the Windows API, including using CreateProcess() or ShellExecute(), to perform a variety of tasks.[76][77]

S0562 SUNSPOT

SUNSPOT used Windows API functions such as MoveFileEx and NtQueryInformationProcess as part of the SUNBURST injection process.[78]

S0242 SynAck

SynAck parses the export tables of system DLLs to locate and call various Windows API functions.[79][80]

S0266 TrickBot

TrickBot uses the Windows API call, CreateProcessW(), to manage execution flow.[81]

G0081 Tropic Trooper

Tropic Trooper has used multiple Windows APIs including HttpInitialize, HttpCreateHttpHandle, and HttpAddUrl.[82]

G0010 Turla

Turla and its RPC backdoors have used APIs calls for various tasks related to subverting AMSI and accessing then executing commands through RPC and/or named pipes.[83]

S0386 Ursnif

Ursnif has used CreateProcessW to create child processes.[84]

S0180 Volgmer

Volgmer executes payloads using the Windows API call CreateProcessW().[85]

S0579 Waterbear

Waterbear can leverage API functions for execution.[86]

S0466 WindTail

WindTail can invoke Apple APIs contentsOfDirectoryAtPath, pathExtension, and (string) compare.[87]

S0161 XAgentOSX

XAgentOSX contains the execFile function to execute a specified file on the system using the NSTask:launch method.[88]

Mitigations

ID Mitigation Description
M1038 Execution Prevention

Identify and block potentially malicious software executed that may be executed through this technique by using application control [89] tools, like Windows Defender Application Control[90], AppLocker, [91] [92] or Software Restriction Policies [93] where appropriate. [94]

Detection

Monitoring API calls may generate a significant amount of data and may not be useful for defense unless collected under specific circumstances, since benign use of API functions are common and difficult to distinguish from malicious behavior. Correlation of other events with behavior surrounding API function calls using API monitoring will provide additional context to an event that may assist in determining if it is due to malicious behavior. Correlation of activity by process lineage by process ID may be sufficient.

Utilization of the Windows API may involve processes loading/accessing system DLLs associated with providing called functions (ex: kernel32.dll, advapi32.dll, user32.dll, and gdi32.dll). Monitoring for DLL loads, especially to abnormal/unusual or potentially malicious processes, may indicate abuse of the Windows API. Though noisy, this data can be combined with other indicators to identify adversary activity.

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