T1486
Data Encrypted for Impact
Description from ATT&CK
Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.(Citation: US-CERT Ransomware 2016)(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017)(Citation: US-CERT SamSam 2018)
In the case of ransomware, it is typical that common user files like Office documents, PDFs, images, videos, audio, text, and source code files will be encrypted (and often renamed and/or tagged with specific file markers). Adversaries may need to first employ other behaviors, such as File and Directory Permissions Modification or System Shutdown/Reboot, in order to unlock and/or gain access to manipulate these files.(Citation: CarbonBlack Conti July 2020) In some cases, adversaries may encrypt critical system files, disk partitions, and the MBR.(Citation: US-CERT NotPetya 2017)
To maximize impact on the target organization, malware designed for encrypting data may have worm-like features to propagate across a network by leveraging other attack techniques like Valid Accounts, OS Credential Dumping, and SMB/Windows Admin Shares.(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017) Encryption malware may also leverage Internal Defacement, such as changing victim wallpapers, or otherwise intimidate victims by sending ransom notes or other messages to connected printers (known as "print bombing").(Citation: NHS Digital Egregor Nov 2020)
In cloud environments, storage objects within compromised accounts may also be encrypted.(Citation: Rhino S3 Ransomware Part 1)
Atomic Tests
Atomic Test #1 - Encrypt files using gpg (Linux)
Uses gpg to encrypt a file
Supported Platforms: linux
auto_generated_guid: 7b8ce084-3922-4618-8d22-95f996173765
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
pwd_for_encrypted_file | the password that you want for the encrypted file | string | passwd |
encrypted_file_path | path to the encrypted file | path | /tmp/passwd.gpg |
input_file_path | path to the file that you want to encrypt | path | /etc/passwd |
encryption_alg | encryption algorithm of the file | string | AES-256 |
Attack Commands: Run with bash!
1
2
echo "#{pwd_for_encrypted_file}" | $which_gpg --batch --yes --passphrase-fd 0 --cipher-algo #{encryption_alg} -o #{encrypted_file_path} -c #{input_file_path}
Cleanup Commands:
1
2
rm #{encrypted_file_path}
Dependencies: Run with bash!
Description: Finds where gpg is located
Check Prereq Commands:
1
2
which_gpg=`which gpg`
Get Prereq Commands:
1
2
(which yum && yum -y install epel-release gpg)||(which apt-get && DEBIAN_FRONTEND=noninteractive apt-get install -y gpg)
Atomic Test #2 - Encrypt files using 7z (Linux)
Uses 7z to encrypt a file
Supported Platforms: linux
auto_generated_guid: 53e6735a-4727-44cc-b35b-237682a151ad
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
pwd_for_encrypted_file | the password that you want for the encrypted file | string | passwd |
encrypted_file_path | path to the encrypted file | path | /tmp/passwd.zip |
input_file_path | path to the file that you want to encrypt | path | /etc/passwd |
Attack Commands: Run with bash!
1
2
$which_7z a -p#{pwd_for_encrypted_file} #{encrypted_file_path} #{input_file_path}
Cleanup Commands:
1
2
3
$which_7z e #{encrypted_file_path}
rm #{encrypted_file_path}
Dependencies: Run with bash!
Description: Finds where 7z is located
Check Prereq Commands:
1
2
which_7z=`which 7z`
Get Prereq Commands:
1
Atomic Test #3 - Encrypt files using ccrypt (Linux)
Attempts to encrypt data on target systems as root to simulate an inturruption authentication to target system. If root permissions are not available then attempts to encrypt data within user's home directory.
Supported Platforms: linux
auto_generated_guid: 08cbf59f-85da-4369-a5f4-049cffd7709f
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
cped_file_path | path where you want your copied file to be | path | /tmp/passwd |
root_input_file_path | path to the file that you want to be encrypted if you are root user | path | /etc/passwd |
user_input_file_path | path to file that you want to be encrypted if you are normal user | path | ~/.bash_history |
impact_command | command to show impact of encryption | string | sudo su |
Attack Commands: Run with bash!
1
2
if [[ $USER == "root" ]]; then $which_ccencrypt #{root_input_file_path}; file #{root_input_file_path}.cpt; #{impact_command}; else $which_ccencrypt #{user_input_file_path}; file #{user_input_file_path}.cpt; #{impact_command}; fi
Cleanup Commands:
1
2
if [[ $USER == "root" ]]; then mv #{cped_file_path} #{root_input_file_path}; else cp #{cped_file_path} #{user_input_file_path}; fi
Dependencies: Run with bash!
Description: Finds where ccencrypt and ccdecrypt is located and copies input file
Check Prereq Commands:
1
2
3
4
which_ccencrypt=`which ccencrypt`
which_ccdecrypt=`which ccdecrypt`
if [[ $USER == "root" ]]; then cp #{root_input_file_path} #{cped_file_path}; else cp #{user_input_file_path} #{cped_file_path}; fi
Get Prereq Commands:
1
2
(which yum && yum -y install epel-release ccrypt)||(which apt-get && DEBIAN_FRONTEND=noninteractive apt-get install -y ccrypt)
Atomic Test #4 - Encrypt files using openssl (Linux)
Uses openssl to encrypt a file
Supported Platforms: linux
auto_generated_guid: 142752dc-ca71-443b-9359-cf6f497315f1
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
private_key_path | path to the private key | path | /tmp/key.pem |
public_key_path | path to the public key | path | /tmp/pub.pem |
encryption_bit_size | size of the bit of encryption | integer | 2048 |
encrypted_file_path | path to the encrypted file | path | /tmp/passwd.zip |
input_file_path | path to the file that you want to encrypt | path | /etc/passwd |
Attack Commands: Run with bash!
1
2
3
4
$which_openssl genrsa -out #{private_key_path} #{encryption_bit_size}
$which_openssl rsa -in #{private_key_path} -pubout -out #{public_key_path}
$which_openssl rsautl -encrypt -inkey #{public_key_path} -pubin -in #{input_file_path} -out #{encrypted_file_path}
Cleanup Commands:
1
2
3
$which_openssl rsautl -decrypt -inkey #{private_key_path} -in #{encrypted_file_path}
rm #{encrypted_file_path}
Dependencies: Run with bash!
Description: Finds where openssl is located
Check Prereq Commands:
1
2
which_openssl=`which openssl`
Get Prereq Commands:
1
Atomic Test #5 - PureLocker Ransom Note
building the IOC (YOUR_FILES.txt) for the PureLocker ransomware https://www.bleepingcomputer.com/news/security/purelocker-ransomware-can-lock-files-on-windows-linux-and-macos/
Supported Platforms: windows
auto_generated_guid: 649349c7-9abf-493b-a7a2-b1aa4d141528
Inputs:
None
Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)
1
2
echo T1486 - Purelocker Ransom Note > %USERPROFILE%\Desktop\YOUR_FILES.txt
Cleanup Commands:
1
2
del %USERPROFILE%\Desktop\YOUR_FILES.txt >nul 2>&1
Atomic Test #6 - Encrypt files using 7z utility - macOS
This test encrypts the file(s) using the 7z utility
Supported Platforms: macos
auto_generated_guid: 645f0f5a-ef09-48d8-b9bc-f0e24c642d72
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
file_password | Password to be provided for archiving the file | string | ARTPass |
encrypted_file_name | Name of the archive to be created | string | ARTArchive.7z |
input_file_path | Path to the file that you want to encrypt | path | ~/test.txt |
Attack Commands: Run with sh!
1
2
7z a -p #{file_password} -mhe=on #{encrypted_file_name} #{input_file_path}
Cleanup Commands:
1
2
rm #{encrypted_file_name}
Dependencies: Run with sh!
Description: Check if 7z command exists on the machine
Check Prereq Commands:
1
2
which 7z
Get Prereq Commands:
1
2
3
4
echo Installing 7z, using brew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
brew install p7zip
Atomic Test #7 - Encrypt files using openssl utility - macOS
This test encrypts the file(s) using the openssl utility
Supported Platforms: macos
auto_generated_guid: 1a01f6b8-b1e8-418e-bbe3-78a6f822759e
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
encryption_option | Specifiy the required encryption option | string | -pbkdf2 |
input_file_path | Path to the file that you want to encrypt | path | ~/test.txt |
output_file_name | Path to the file that you want to encrypt | string | ARTFile |
Attack Commands: Run with sh!
1
2
openssl enc #{encryption_option} -in #{input_file_path} -out #{output_file_name}
Cleanup Commands:
1
2
rm #{output_file_name}
Atomic Test #8 - Data Encrypted with GPG4Win
Gpg4win is a Windows tool (also called Kleopatra which is the preferred certificate manager) that uses email and file encryption packages for symmetric encryption. It is used by attackers to encrypt disks. User will need to add pass phrase to encrypt file as automation is not allowed under newer versions.
Supported Platforms: windows
auto_generated_guid: 4541e2c2-33c8-44b1-be79-9161440f1718
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
GPG_Exe_Location | Path of the GPG program | path | C:\Program Files (x86)\GnuPG\bin\gpg.exe |
File_to_Encrypt_Location | Path of File | path | $env:temp\test.txt |
Attack Commands: Run with powershell!
1
2
cmd /c '#{GPG_Exe_Location}' -c '#{File_to_Encrypt_Location}'
Cleanup Commands:
1
2
remove-item '#{File_to_Encrypt_Location}.gpg' -force -erroraction silentlycontinue | out-null
Dependencies: Run with powershell!
Description: GPG must exist at (#{GPG_Exe_Location})
Check Prereq Commands:
1
2
if (test-path '#{GPG_Exe_Location}'){exit 0} else {exit 1}
Get Prereq Commands:
1
2
3
4
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
invoke-webrequest "https://files.gpg4win.org/gpg4win-4.1.0.exe" -outfile "PathToAtomicsFolder\..\ExternalPayloads\gpginstall.exe"
cmd /c "PathToAtomicsFolder\..\ExternalPayloads\gpginstall.exe" /S