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Ransom.Win32.SPOOSH.THGAGBC

 Analysis by: John Rainier Navato

 ALIASES:

Generic.Ransom.DCRTR.7E80656D (BITDEFENDER)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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 connects to certain websites to send and receive information.

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

  TECHNICAL DETAILS

File Size:

5,153,366 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

18 Jul 2023

Payload:

Connects to URLs/IPs, Collects system information, Encrypts files, Modifies system registry, Terminates processes, Drops files

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 adds the following processes:

  • %System%\cmd.exe /C "vssadmin delete shadows /all /quiet"
  • %System%\cmd.exe /C "rd /s /q %systemdrive%\$Recycle.bin"
  • %System%\WindowsPowershell\v1.0\powershell.exe -Command "New-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System' -Name EnableLinkedConnections -Value 1 -PropertyType 'DWord'"
  • %System%\WindowsPowershell\v1.0\powershell.exe -Command "get-service LanmanWorkstation |Restart-Service –Force"
  • attrib.exe -R {Directory to Encrypt}\{File Name to Encrypt}.{File Extension to Encrypt}
  • mshta.exe %System Root%\Boot\cs-CZ\information.hta

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

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Printers\SettingsLow
DI = {8 Random Alphanumeric Characters}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLinkedConnections = 1

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

  • %AppDataLocal%\wallpaper.jpg

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

Process Termination

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

  • Agntsvc.exe
  • Dbeng50.exe
  • Dbsnmp.exe
  • Encsvc.exe
  • Excel.exe
  • Firefox.exe
  • Infopath.exe
  • Isqlplussvc.exe
  • Msaccess.exe
  • Mspub.exe
  • Mydesktopqos.exe
  • Mydesktopservice.exe
  • Notepad.exe
  • Ocautoupds.exe
  • Ocomm.exe
  • Ocssd.exe
  • Onenote.exe
  • Oracle.exe
  • Outlook.exe
  • Powerpnt.exe
  • Sqbcoreservice.exe
  • Sql.exe
  • Steam.exe
  • Synctime.exe
  • Tbirdconfig.exe
  • Thebat.exe
  • Thunderbird.exe
  • Ut.exe
  • Utweb.exe
  • Visio.exe
  • Winword.exe
  • Wordpad.exe
  • Xfssvccon.exe

Dropping Routine

This Ransomware drops the following files:

  • %AppDataLocal%\wallpaper.jpg

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

Information Theft

This Ransomware gathers the following data:

  • Processor Name
  • Memory
  • Internal IP Address
  • Manufacturer
  • OS Version
  • Computer Name
  • Product Name
  • External IP Address
  • Device ID

Other Details

This Ransomware adds the following registry keys:

HKEY_CURRENT_USER\Printers\SettingsLow

It connects to the following website to send and receive information:

  • tcp://{BLOCKED}.{BLOCKED}.154.137:21119

It does the following:

  • It terminates itself if the computer language is Russian
  • It downloads the desktop wallpaper to be set from the following url:
    • https://i.{BLOCKED}g.cc/JzpfvBFf/wallapaper.jpg
  • It connects to the following url to identify the machine's external IP address:
    • https://{BLOCKED}rnalip.com

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • $RECYCLE.BIN
  • $Recycle.Bin
  • $WINDOWS.~BT
  • $WINDOWS.~WS
  • $WinREAgent
  • $Windows.~WS
  • AdwCleaner
  • AppData
  • dev
  • Documents and Settings
  • Hyberfil
  • MSOCache
  • Pagefile
  • PerfLogs
  • Program Files
  • Program Files (x86)
  • ProgramData
  • Recovery
  • SYSTEM.SAV
  • System Volume Information
  • Thumbs
  • Thumbs.db
  • Windows.old
  • windows.old
  • Windows.old.000
  • windows.old.000

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

  • .[[{8 Random Alphanumeric Characters}]].[[{Email Address}]].sophos

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

  • {Encrypted Directory}\information.hta
  • %System Root%\Boot\cs-CZ\information.hta

It avoids encrypting files with the following file extensions:

  • .adv
  • .ani
  • .bat
  • .com
  • .cpl
  • .cur
  • .deskthemepack
  • .Devos
  • .diagcab
  • .diagcfg
  • .diagpkg
  • .dll
  • .drv
  • .faust
  • .hlp
  • .hta
  • .icl
  • .icns
  • .ico
  • .ics
  • .idx
  • .inf
  • .ini
  • .joker
  • .key
  • .ldf
  • .lnk
  • .lock
  • .log
  • .mkp
  • .mod
  • .mpa
  • .msc
  • .msp
  • .msstyles
  • .msu
  • .nls
  • .nomedia
  • .ocx
  • .prf
  • .ps1
  • .regtrans-ms
  • .rom
  • .rtp
  • .scr
  • .shs
  • .sophos
  • .spl
  • .sys
  • .theme
  • .themepack
  • .tmp
  • .wpx

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.582.02

FIRST VSAPI PATTERN DATE:

20 Jul 2023

VSAPI OPR PATTERN File:

18.583.00

VSAPI OPR PATTERN Date:

21 Jul 2023

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Printers\SettingsLow
    • DI = {8 Random Alphanumeric Characters}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • EnableLinkedConnections = 1

Step 4

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Printers
    • SettingsLow

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • {Encrypted Directory}\information.hta
  • %AppDataLocal%\wallpaper.jpg

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.SPOOSH.THGAGBC. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:

Step 7

Restore encrypted files from backup.


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