Ransom.Win32.DARKRACE.THCOFBD

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 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:

• %ProgramData%\icon.ico → icon for encrypted files

(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:

• vssadmin Delete Shadows /All /Quiet
• wmic shadowcopy delete /nointeractive
• cmd %ProgramData%\1.bat
• ping 127.0.0.1 -n 2
• taskkill /f /im {process}

(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:

• CheckMutex

Other System Modifications

This Ransomware adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.f58A66B51
{default} = f58A66B51 file → register extension of encrypted file to system

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.f58A66B51\DefaultIcon
{default} = %ProgramData%\icon.ico → set default icon for encrypted files

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number} → deleted afterwards

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number}
Owner = {hex values}

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number}
SessionHash = {hex values}

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number}
Sequence = 1

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number}
RegFiles0000 = {full path of file to encrypt}

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session{number}
RegFilesHash = {hex values}

Process Termination

This Ransomware terminates the following services if found on the affected system:

• vss
• sql
• svc$
• memtas
• mepocs
• msexchange
• sophos
• veeam
• backup
• GxVss
• GxBlr
• GxFWD
• GxCVD
• GxCIMgr

It terminates the following processes if found running in the affected system's memory:

• sql
• oracle
• mysq
• chrome
• veeam
• firefox
• excel
• msaccess
• onenote
• outlook
• powerpnt
• winword
• wuauclt

Other Details

This Ransomware does the following:

• It encrypts the following in the affected system:
  • Local Drives
  • Network Shares
• It clears event logs to hide its malicious activities.
• It shuts down the system to prevent access from the user.
• It empties the recycle bin of the affected system.

Ransomware Routine

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

• bootmgr
• autorun.inf
• boot.ini
• bootfont.bin
• bootsect.bak
• desktop.ini
• iconcache.db
• ntldr
• ntuser.dat
• ntuser.dat.log
• ntuser.ini
• thumbs.db
• GDIPFONTCACHEV1.DAT
• d3d9caps.dat

It avoids encrypting files with the following strings in their file path:

• $recycle.bin
• config.msi
• $windows.~bt
• $windows.~ws
• windows
• boot
• program files
• program files(x86)
• programdata
• system volume information
• torbrowser
• windows.old
• intel
• msocache
• perflogs
• x64dbg
• public
• all users
• default
• microsoft
• appdata

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

• {original filename}.{original extension}.f58A66B51

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

• {encrypted directory}\Readme-f58A66B51.txt
  

It avoids encrypting files with the following file extensions:

• 386
• adv
• ani
• bat
• bin
• cab
• cmd
• com
• cpl
• cur
• deskthemepack
• diagcab
• diagcfg
• diagpkg
• dll
• drv
• exe
• hlp
• icl
• icns
• ico
• ics
• idx
• lnk
• mod
• mpa
• msc
• msp
• msstyles
• msu
• nls
• nomedia
• ocx
• prf
• ps1
• rom
• rtp
• scr
• shs
• spl
• sys
• theme
• themepack
• wpx
• lock
• key
• hta
• msi
• pdb
• search-ms