T1055.004
Process Injection: Asynchronous Procedure Call
Description from ATT&CK
Adversaries may inject malicious code into processes via the asynchronous procedure call (APC) queue in order to evade process-based defenses as well as possibly elevate privileges. APC injection is a method of executing arbitrary code in the address space of a separate live process.
APC injection is commonly performed by attaching malicious code to the APC Queue (Citation: Microsoft APC) of a process's thread. Queued APC functions are executed when the thread enters an alterable state.(Citation: Microsoft APC) A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point QueueUserAPC can be used to invoke a function (such as LoadLibrayA pointing to a malicious DLL).
A variation of APC injection, dubbed "Early Bird injection", involves creating a suspended process in which malicious code can be written and executed before the process' entry point (and potentially subsequent anti-malware hooks) via an APC. (Citation: CyberBit Early Bird Apr 2018) AtomBombing (Citation: ENSIL AtomBombing Oct 2016) is another variation that utilizes APCs to invoke malicious code previously written to the global atom table.(Citation: Microsoft Atom Table)
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 APC 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 C#
Process Injection using C# reference: https://github.com/pwndizzle/c-sharp-memory-injection Excercises Five Techniques
- Process injection
- ApcInjectionAnyProcess
- ApcInjectionNewProcess
- IatInjection
- ThreadHijack Upon successful execution, cmd.exe will execute T1055.exe, which exercises 5 techniques. Output will be via stdout.
Supported Platforms: windows
auto_generated_guid: 611b39b7-e243-4c81-87a4-7145a90358b1
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
exe_binary | Output Binary | path | PathToAtomicsFolder\T1055.004\bin\T1055.exe |
Attack Commands: Run with command_prompt!
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#{exe_binary}
Dependencies: Run with powershell!
Description: #{exe_binary} must be exist on system.
Check Prereq Commands:
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if (Test-Path #{exe_binary}) {exit 0} else {exit 1}
Get Prereq Commands:
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New-Item -Type Directory (split-path #{exe_binary}) -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1055.004/bin/T1055.exe" -OutFile "#{exe_binary}"