Ransom.Win32.HIDDENTEAR.B

 Analysis by: Leidryn Saludez

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size:

2,593,280 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

26 Mar 2024

Payload:

Drops files, Encrypts files, Displays message/message boxes, Terminates processes

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:

  • %Temp%\update.{Random}.mwt
  • %Program Data%\encryption.{10 Random Characters}.enc.key.plain
  • %Program Data%\encryption.{10 Random Characters}.enc.key
  • %Temp%\encryption.log → if already exist, it will not proceed to its malicious routine

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

It adds the following processes:

  • netsh advfirewall firewall add rule name="Port 80" dir=out action=block protocol=TCP remoteport=80
  • netsh advfirewall firewall add rule name="Port 443" dir=out action=block protocol=TCP remoteport=443
  • netsh advfirewall firewall add rule name="Port 4122out" dir=out action=block protocol=TCP remoteport=4122 localport=4122
  • netsh advfirewall firewall add rule name="Port 4118-4119out" dir=out action=block protocol=TCP remoteport=4118-4119 localport=4118-4119
  • netsh advfirewall firewall add rule name="Port 5274-5275out" dir=out action=block protocol=TCP remoteport=5274-5275 localport=5274-5275
  • netsh advfirewall firewall add rule name="Port 4122in" dir=in action=block protocol=TCP remoteport=4122 localport=4122
  • netsh advfirewall firewall add rule name="Port 4118-4119in" dir=in action=block protocol=TCP remoteport=4118-4119 localport=4118-4119
  • netsh advfirewall firewall add rule name="Port 5274-5275in" dir=in action=block protocol=TCP remoteport=5274-5275 localport=5274-5275
  • %Temp%\update.{Random}.mwt true %ProgramData%\encryption.{10 Random Characters}.enc.key.plain
  • cmd /c "taskkill /F /IM {Target 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.)

Process Termination

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

  • via taskkill /F /IM:
    • pg_ctl.exe
    • postgres.exe
    • mysqld.exe
    • sqlservr.exe
    • sqlwriter.exe
    • sqlceip.exe

Other Details

This Ransomware does the following:

  • It targets files and folders in local drives, network shares, and removable drives.
  • It encrypts files related to Microsoft SQL which contain the following strings in their file path:
    • {Drive Letter}\Program Files\*MSSQL*
    • {Drive Letter}\Program Files (x86)\*MSSQL*
  • It adds the following processes if these Windows Firewall rule exists:
    • netsh advfirewall firewall delete rule name="Port 80"
    • netsh advfirewall firewall delete rule name="Port 443"
    • netsh advfirewall firewall delete rule name="Port 4122in"
    • netsh advfirewall firewall delete rule name="Port 4118-4119in"
    • netsh advfirewall firewall delete rule name="Port 5274-5275in"
    • netsh advfirewall firewall delete rule name="Port 4122out"
    • netsh advfirewall firewall delete rule name="Port 4118-4119out"
    • netsh advfirewall firewall delete rule name="Port 5274-5275out"
  • It requires a specific file name and path to proceed to its malicious routine. → "%Temp%\update.mwt"
    • When executed without this file name, it will repeatedly create %Temp%\update.{Random}.mwt until it crashed the system.
  • It requires to be executed as an administrator.
    • When executed without admin privilege, it will encrypt network shares and will not create processes for Windows Firewall rules.

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

Ransomware Routine

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

  • .enc.key
  • .enc
  • .lnk
  • .reg
  • .sys
  • .tmp
  • @RANSOMWARE@README.md
  • $Recycle.Bin
  • $WinREAgent
  • AppData
  • desktop.ini
  • Desktop.ini
  • eScan
  • file_encryption
  • ntuser
  • NTUSER
  • PerfLogs
  • Program Files
  • Recovery
  • Windows

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

  • .enc

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

  • %Desktop%\@RANSOMWARE@README.md
  • {Encrypted path}\@RANSOMWARE@README.md

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.242.06

FIRST VSAPI PATTERN DATE:

27 Mar 2024

VSAPI OPR PATTERN File:

19.243.00

VSAPI OPR PATTERN Date:

28 Mar 2024

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

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.  
  • %Temp%\update.{Random}.mwt
  • %Program Data%\encryption.{10 Random Characters}.enc.key.plain
  • %Program Data%\encryption.{10 Random Characters}.enc.key

Step 4

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.HIDDENTEAR.B. 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 5

Restore encrypted files from backup.


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