T1055.011 - Process Injection: Extra Window Memory Injection

Description from ATT&CK

Adversaries may inject malicious code into process via Extra Window Memory (EWM) in order to evade process-based defenses as well as possibly elevate privileges. EWM injection is a method of executing arbitrary code in the address space of a separate live process. Before creating a window, graphical Windows-based processes must prescribe to or register a windows class, which stipulate appearance and behavior (via windows procedures, which are functions that handle input/output of data).(Citation: Microsoft Window Classes) Registration of new windows classes can include a request for up to 40 bytes of EWM to be appended to the allocated memory of each instance of that class. This EWM is intended to store data specific to that window and has specific application programming interface (API) functions to set and get its value. (Citation: Microsoft GetWindowLong function) (Citation: Microsoft SetWindowLong function) Although small, the EWM is large enough to store a 32-bit pointer and is often used to point to a windows procedure. Malware may possibly utilize this memory location in part of an attack chain that includes writing code to shared sections of the process’s memory, placing a pointer to the code in EWM, then invoking execution by returning execution control to the address in the process’s EWM. Execution granted through EWM injection may allow access to both the target process's memory and possibly elevated privileges. Writing payloads to shared sections also avoids the use of highly monitored API calls such as WriteProcessMemory and CreateRemoteThread.(Citation: Elastic Process Injection July 2017) More sophisticated malware samples may also potentially bypass protection mechanisms such as data execution prevention (DEP) by triggering a combination of windows procedures and other system functions that will rewrite the malicious payload inside an executable portion of the target process. (Citation: MalwareTech Power Loader Aug 2013) (Citation: WeLiveSecurity Gapz and Redyms Mar 2013) Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via EWM injection may also evade detection from security products since the execution is masked under a legitimate process.

Atomic Tests

Atomic Test #1 - Process Injection via Extra Window Memory (EWM) x64 executable

Hooks functions of main process to inject a payload via Extra Window Memory (EWM) injection technique

Supported Platforms: Windows

auto_generated_guid: 93ca40d2-336c-446d-bcef-87f14d438018


| Name | Description | Type | Default Value | |——|————-|——|—————| | arch | Architecture of payload. One of (x64, x86) | string | x64| | exe_binary | PE binary for EWM injection | path | PathToAtomicsFolder\T1055.011\bin\T1055.011#{arch}.exe| | payload_file | raw payload to inject | path | PathToAtomicsFolder\T1055.011\bin\payload.exe#{arch}.bin|

Attack Commands: Run with


Cleanup Commands:

Get-Process -Name Notepad -ErrorAction SilentlyContinue | Stop-Process -Force

Dependencies: Run with

Description: T1055.011x64.exe and payload must exist on disk at specified location (#{exe_binary} and #{payload_file})
Check Prereq Commands:
if (Test-Path #{exe_binary}) {exit 0} else {exit 1}
Get Prereq Commands:
New-Item -Type Directory (split-path #{exe_binary}) -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1055.011/bin/T1055.011_#{arch}.exe" -OutFile "#{exe_binary}" -UseBasicParsing
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1055.011/bin/payload.exe_#{arch}.bin" -OutFile "#{payload_file}" -UseBasicParsing