Ransom.Win32.XORIST.THLODBC

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 encrypts files with specific file extensions. It drops files as ransom note.

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 and executes the following files:

• %User Temp%\6TV8KH596tB4r6Q.exe → RegAsm.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:

• %Windows%\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe

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

It injects codes into the following process(es):

• %Windows%\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe

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

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.xro

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBEproce

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\DefaultIcon

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\shell

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\shell\open

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\shell\open\
command

It modifies the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Alcmeter = %User Temp%\6TV8KH596tB4r6Q.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.xro
(Default) = YWOOOABBZNYCLBE

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE
(Default) = CRYPTED!

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\DefaultIcon
(Default) = %User Temp%\6TV8KH596tB4r6Q.exe,0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
YWOOOABBZNYCLBE\shell\open\
command
(Default) = %User Temp%\6TV8KH596tB4r6Q.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
upd = %User Temp%\{Malware Name}

Other Details

This Ransomware displays the following message boxes:

• Asks for password for decryption (if %User Temp%\6TV8KH596tB4r6Q.exe already exists upon execution)

(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).)

Ransomware Routine

This Ransomware encrypts files with the following extensions:

• .zip
• .rar
• .7z
• .tar
• .gzip
• .jpg
• .jpeg
• .psd
• .cdr
• .dwg
• .max
• .bmp
• .gif
• .png
• .doc
• .docx
• .xls
• .xlsx
• .ppt
• .pptx
• .txt
• .pdf
• .djvu
• .htm
• .html
• .mdb
• .cer
• .p12
• .pfx
• .kwm
• .pwm
• .1cd
• .md
• .mdf
• .dbf
• .odt
• .vob
• .ifo
• .lnk
• .torrent
• .mov
• .m2v
• .3gp
• .mpeg
• .mpg
• .flv
• .avi
• .mp4
• .wmv
• .divx
• .mkv
• .mp3
• .wav
• .flac
• .ape
• .wma
• .ac3

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

• .xro

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

• It drops the following file(s) as ransom note:
  {Encrypted Directory}\HOW TO DECRYPT FILES.txt