Ransom.Win32.VENUS.THIABBB

December 01, 2022
 Analysis by: Ricardo III Valdez
 ALIASES:

HEUR:Trojan-Ransom.Win32.Generic (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes then deletes itself afterward.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

230,912 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Sep 2022

Payload:

Displays message/message boxes, Displays graphics/image, Encrypts files, Modifies system registry

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 copies of itself into the affected system and executes them:

  • %Windows%\{Malware Filename}.exe

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

It drops the following files:

  • %Windows%\{Derived from System Info}{Volume Serial Number in Decimal Value}.png ← (20 characters)
  • %User Temp%\{Derived from System Info}{Volume Serial Number in Decimal Value}.jpg ← (20 characters)

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %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%\{Malware Filename}.exe" g g g o n e123
  • /c ping localhost -n 3 > nul & del {Malware File Path} ← Deletes the original malware file
  • /C taskkill /F /IM {Process Name} ← Terminates a hardcoded list of processes
  • wbadmin delete catalog -quiet ← Deletes event logs
  • vssadmin.exe delete shadows /all /quiet
  • wmic SHADOWCOPY DELETE ← Deletes shadow copy volumes
  • bcdedit.exe /set {current} nx AlwaysOff ← Disables data execution prevention

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

It executes then deletes itself afterward.

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

  • {Derived from System Info}{Volume Serial Number in Decimal Value} ← (20 characters)

Autostart Technique

This Ransomware creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Malware Filename} = %Windows%\{Malware Filename}.exe

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
pbsecGOOD = {Random Characters}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
secpbGOOD = {Random Characters}

It changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{Derived from System Info}{Volume Serial Number in Decimal Value}.jpg

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

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
  • firefoxconfig.exe
  • infopath.exe
  • isqlplussvc.exe
  • msaccess.exe
  • msftesql.exe
  • mspub.exe
  • mydesktopqos.exe
  • mydesktopservice.exe
  • mysqld.exe
  • mysqld-nt.exe
  • mysqld-opt.exe
  • ocautoupds.exe
  • ocomm.exe
  • ocssd.exe
  • onenote.exe
  • oracle.exe
  • outlook.exe
  • powerpnt.exe
  • sqbcoreservice.exe
  • sqlagent.exe
  • sqlbrowser.exe
  • sqlservr.exe
  • sqlwriter.exe
  • synctime.exe
  • tbirdconfig.exe
  • thebat64.exe
  • thunderbird.exe
  • winword.exe
  • wordpad.exe
  • xfssvccon.exe

Other Details

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.venus\DefaultIcon
(Default) = {Derived from System Info}{Volume Serial Number in Decimal Value}.png

It does the following:

  • It changes the icons of encrypted files with the following image:
  • It empties the Recycle Bin

Ransomware Routine

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

  • {Encrypted Drive/Folder}\README.html
  • %User Temp%\{Derived from System Info}{Volume Serial Number in Decimal Value}.hta

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

17.808.02

FIRST VSAPI PATTERN DATE:

12 Sep 2022

VSAPI OPR PATTERN File:

17.809.00

VSAPI OPR PATTERN Date:

13 Sep 2022

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • TROJ.Win32.TRX.XXPE50FFF061

Step 2

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 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

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\Software\Microsoft\Windows\CurrentVersion\Run
    • {Malware Filename} = %Windows%\{Malware Filename}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • pbsecGOOD = {Random Characters}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • secpbGOOD = {Random Characters}

Step 6

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • .venus

Step 7

Search and delete these files

[ 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.
  • %Windows%\{Malware Filename}.exe
  • %Windows%\{Derived from System Info}{Volume Serial Number in Decimal Value}.png
  • %User Temp%\{Derived from System Info}{Volume Serial Number in Decimal Value}.jpg
  • %User Temp%\{Derived from System Info}{Volume Serial Number in Decimal Value}.hta
  • {Encrypted Drive/Folder}\README.html

Step 8

Reset your Desktop properties

[ Learn More ]

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.VENUS.THIABBB. 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 this Knowledge Base page for more information.

Step 10

Restore encrypted files from backup.


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