Ransom.Win32.CELANCYC.THCCABC

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It gathers certain information on the affected computer.

It drops files as ransom note. It avoids encrypting files with the following file extensions.

Arrival Details

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Ransomware drops the following files:

• {Malware File Path}\MSVCR100.dll → Contains the logs of the ransomware
• %ProgramData%\SBOX → Contains the encryption key
• %ProgramData%\LPW4.tmp → Contains the command to shutdown or restart the system

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

It adds the following processes:

• cmd.exe /c SCHTASKS.exe /Create /RU \"NT AUTHORITY\SYSTEM\" /sc onstart /TN \"Windows Update Beta\" /TR \"{Malware File Path}" /F"
• cmd.exe "/c ""%ProgramData%\LPW4.tmp""/SHUTDOWN" →When -power shutdown parameter is used
• cmd.exe "/c ""%ProgramData%\LPW4.tmp"" /RESTART" →When -power restart parameter is used
• cmd.exe /c SCHTASKS.exe /Delete /TN \"Windows Update Beta\" /TR \"{Malware File Path}" /F"
• cmd.exe "/c ping 127.0.0.1 -n 5 > nul & del {Malware File Path}"" → When -selfdel is used

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit), or C:\Documents and Settings\All Users on Windows Server 2003(32-bit), 2000(32-bit) and XP.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\CylanceMutex

Autostart Technique

The scheduled task executes the malware every:

• System Startup

Information Theft

This Ransomware gathers the following information on the affected computer:

• IP
• UID
• PID
• Version
• OS
• Computer name
• USername
• Domain
• RAM
• CPU
• Disk informations

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

• {BLOCKED}.{BLOCKED}.{BLOCKED}.175/r1.php
• {BLOCKED}.{BLOCKED}.{BLOCKED}.175/r2.php

Other Details

This Ransomware does the following:

• It uses WQL to delete shadow copies
• Empty RecycledBin

It accepts the following parameters:

• -path -Specify the path to Encrypt
• -mode {option}
• Option can be any of the following:
• full → Encrypts all file
• fast → Encrypts the first 1MB of the file
• split → Encrypts file from a specific offset and requires the -skip parameter to be used.
• -skip → Specify the number of bytes to be skipped during the encryption process.
• -power (restart or shutdown) → Specify actions to be taken after completing the task, either restart or shutdown the system
• -console → Display encryption details
  
• -nomutex → Execute without generating a mutex
• -nonetdrive → Exclude network drive from encryption
• -selfdel → Delete itself after encryption

It adds the following scheduled tasks:

• Windows Update Beta

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

• ntldr
• ntluser.dat
• bootsect.bak
• ntuser.dat.log
• autorun.inf
• thumbs.db
• iconcache.db
• bootfont.bin
• boot.ini
• desktop.ini
• ntuser.ini
• bootmgr
• BOOTNXT
• CYLANCE_README.txt
• LPW4.tmp
• MSVCR100.dll
• LLKFTP.bmp
• SBOX

It avoids encrypting files found in the following folders:

• Windows
• $Windows.~bt
• $windows.~ws
• windows.old
• windows nt
• All Users
• Public
• Boot
• Intel
• Perflogs
• System Volume Information
• MSOCache
• $RECYCLE.BIN
• Default
• Config.Msi
• tor browser
• microsoft
• google
• yandex

It appends the following extension to the file name of the encrypted files:

• .Cylance

It drops the following file(s) as ransom note:

• CYLANCE_README.txt
  

It avoids encrypting files with the following file extensions:

• dll
• exe
• sys
• drv
• efi
• msi
• lnk
• Cylance