T1023.md

T1023 - Shortcut Modification

Description from ATT&CK

Shortcuts or symbolic links are ways of referencing other files or programs that will be opened or executed when the shortcut is clicked or executed by a system startup process. Adversaries could use shortcuts to execute their tools for persistence. They may create a new shortcut as a means of indirection that may use [Masquerading](https://attack.mitre.org/techniques/T1036) to look like a legitimate program. Adversaries could also edit the target path or entirely replace an existing shortcut so their tools will be executed instead of the intended legitimate program.

Atomic Tests

• Atomic Test #1 - Shortcut Modification

• Atomic Test #2 - Create shortcut to cmd in startup folders

Atomic Test #1 - Shortcut Modification

This test to simulate shortcut modification and then execute. example shortcut (*.lnk , .url) strings check with powershell; gci -path "C:\Users" -recurse -include *.url -ea SilentlyContinue | Select-String -Pattern "exe" | FL. Upon execution, calc.exe will be launched.

Supported Platforms: Windows

Inputs:

Name	Description	Type	Default Value
shortcut_file_path	shortcut modified and execute	path	%temp%\T1023_modified_shortcut.url

Attack Commands: Run with command_prompt!

echo [InternetShortcut] > #{shortcut_file_path}
echo URL=C:\windows\system32\calc.exe >> #{shortcut_file_path}
#{shortcut_file_path}

Cleanup Commands:

del -f #{shortcut_file_path} >nul 2>&1

Atomic Test #2 - Create shortcut to cmd in startup folders

LNK file to launch CMD placed in startup folder. Upon execution, open File Explorer and browse to "%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup" to view the new shortcut.

Supported Platforms: Windows

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

$Shell = New-Object -ComObject ("WScript.Shell")
$ShortCut = $Shell.CreateShortcut("$env:APPDATA\Microsoft\Windows\Start Menu\Programs\Startup\T1023.lnk")
$ShortCut.TargetPath="cmd.exe"
$ShortCut.WorkingDirectory = "C:\Windows\System32";
$ShortCut.WindowStyle = 1;
$ShortCut.Description = "T1023.";
$ShortCut.Save()

$Shell = New-Object -ComObject ("WScript.Shell")
$ShortCut = $Shell.CreateShortcut("$env:ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\T1023.lnk")
$ShortCut.TargetPath="cmd.exe"
$ShortCut.WorkingDirectory = "C:\Windows\System32";
$ShortCut.WindowStyle = 1;
$ShortCut.Description = "T1023.";
$ShortCut.Save()

Cleanup Commands:

Remove-Item "$env:APPDATA\Microsoft\Windows\Start Menu\Programs\Startup\T1023.lnk" -ErrorAction Ignore
Remove-Item "$env:ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\T1023.lnk" -ErrorAction Ignore