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Ransom.Win32.HELDOWN.THJAGBD

January 07, 2025
 Analysis by: John Rainier Navato
 ALIASES:

Ransom:Win32/Helldown.YCE!MTB (MICROSOFT)

 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 encrypts files found in specific folders. It drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

669,189 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Oct 2024

Payload:

Disables AV, Drops files, Encrypts files, 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:

  • %ProgramData%\xx.ico
  • %ProgramData%\1.bat

(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.)

It adds the following processes:

  • cmd /c wmic shadowcopy delete /noninteractive
  • cmd /c "vssadmin Delete Shadows /All /Quiet"
  • cmd /c %ProgramData%\1.bat
  • ping 127.0.0.1 -n 2
  • taskkill /f /im sql*
  • taskkill /f /im oracle*
  • taskkill /f /im mysq*
  • taskkill /f /im veeam*
  • taskkill /f /im firefox*
  • taskkill /f /im excel*
  • taskkill /f /im msaccess*
  • taskkill /f /im onenote*
  • taskkill /f /im outlook*
  • taskkill /f /im powerpnt*
  • taskkill /f /im winword*
  • taskkill /f /im wuauclt*
  • cmd /c "taskkill /f /im cmd.exe & taskkill /f /im conhost.exe"
  • cmd /c "ping 127.0.0.1 & del %ProgramData%\1.bat & del {Malware File Path}\{Malware File Name} & shutdown -r -f -t 0"

(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.)

Other System Modifications

This Ransomware adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\Classes\.uQlf
(Default) = uQlfIcon

HKEY_LOCAL_MACHINE\Classes\uQlfIcon\
DefaultIcon
(Default) = %ProgramData%\xx.ico

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\Classes
uQlfIcon =

HKEY_LOCAL_MACHINE\Classes
.uQlf =

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • backup
  • GxBlr
  • GxCIMgr
  • GxCVD
  • GxFWD
  • GxVss
  • memtas
  • mepocs
  • msexchange
  • sophos
  • sql
  • svc$
  • veeam
  • vss

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

  • excel
  • firefox
  • msaccess
  • mysq
  • onenote
  • oracle
  • outlook
  • powerpnt
  • veeam
  • winword
  • wuauclt

Other Details

This Ransomware encrypts files with the following extensions:

  • .ldf
  • .mdf
  • .pko
  • Extensions not in the whitelist

It does the following:

  • It changes the encrypted file icon to the following image:
  • It encrypts network shares.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • Program Files\Microsoft SQL Server
  • Program Files (x86)\Microsoft SQL Server
  • Folders not in the whitelist

It avoids encrypting files with the following strings in their file name:

  • autorun.inf
  • boot.ini
  • bootfont.bin
  • bootmgr
  • bootsect.bak
  • d3d9caps.dat
  • desktop.ini
  • GDIPFONTCACHEV1.DAT
  • iconcache.db
  • ntldr
  • ntuser.dat
  • ntuser.dat.log
  • ntuser.ini
  • thumbs.db

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

  • $recycle.bin
  • $windows.~bt
  • $windows.~ws
  • all users
  • appdata
  • boot
  • config.msi
  • default
  • inetpub
  • intel
  • microsoft
  • msocache
  • perflogs
  • program files
  • program files (x86)
  • programdata
  • public
  • system volume information
  • tor browser
  • windows
  • windows.old
  • x64dbg

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

  • .uQlf

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

  • {Encrypted Path}\Readme.uQlf.txt

It avoids encrypting files with the following file extensions:

  • .386
  • .adv
  • .AlHOqPJT
  • .ani
  • .azGOWrO
  • .bat
  • .bfKPKp
  • .bin
  • .BNNAlE
  • .BodtTcy
  • .bSzsD
  • .BUWSMiK
  • .cab
  • .CDPhao
  • .CgoPb
  • .cKFNxjY
  • .ckyxN
  • .CKzE
  • .cmd
  • .com
  • .cpl
  • .CQeew
  • .cur
  • .DdfoPwvC
  • .DEjmSDQe
  • .deskthemepack
  • .diagcab
  • .diagcfg
  • .diagpkg
  • .dll
  • .dMOAgi
  • .dmwe
  • .drv
  • .DuWP
  • .eiowF
  • .EKhdzKM
  • .eObbg
  • .euBqJW
  • .eucHUnd
  • .exe
  • .exTln
  • .fHAJkKFD
  • .fHrjx
  • .fNar
  • .FpnUh
  • .fXtM
  • .Gatpya
  • .GbaI
  • .GCNcYE
  • .GGFtMd
  • .gHefG
  • .GhXRL
  • .GVcIyr
  • .gxEuSv
  • .HGjAB
  • .HgsVQnUC
  • .HhWtbN
  • .HKTyQ
  • .hlp
  • .hta
  • .huABnaK
  • .ibsewNOI
  • .icl
  • .icns
  • .ico
  • .ics
  • .iCSkVcP
  • .idx
  • .ipST
  • .ISkoqBz
  • .iykIj
  • .izfvNIo
  • .JaImV
  • .JhrCrk
  • .jjcXWfnl
  • .key
  • .KIXsYv
  • .kRDsqM
  • .kRsYZJyQ
  • .LENNw
  • .liNjEEj
  • .lnk
  • .lock
  • .LZJK
  • .LzwE
  • .MBhSH
  • .mDGs
  • .MjVAzUB
  • .mod
  • .MooOzu
  • .mpa
  • .mRTanA
  • .MRVpcx
  • .msc
  • .msi
  • .msp
  • .msstyles
  • .msu
  • .nbhtRyt
  • .NbKCPV
  • .niSsKNWX
  • .nls
  • .NlSdI
  • .nomedia
  • .NScx
  • .NWvlhq
  • .nWzO
  • .OBEEmY
  • .ocx
  • .Oyfx
  • .pdb
  • .POrcRK
  • .prf
  • .ps1
  • .Puolu
  • .pxtrbnaJ
  • .QHMSXf
  • .qmoTzFmD
  • .QScYYgTO
  • .QtJeWT
  • .QTTiDhUZ
  • .QypnyNT
  • .RHlRYeu
  • .RlaXjvjK
  • .RLpYbR
  • .RMkWTRw
  • .Rnif
  • .rom
  • .RQJGa
  • .rtp
  • .ruIskqo
  • .RvXHag
  • .sAsVu
  • .scpOg
  • .scr
  • .search-ms
  • .shs
  • .SKAw
  • .spl
  • .srem
  • .sthOKQU
  • .SUaLl
  • .sys
  • .tblnocn
  • .theme
  • .themepack
  • .tnrKjo
  • .TwqMEzmf
  • .UNEzGdSD
  • .UpPLjwr
  • .uQlf
  • .uvbg
  • .uZjKDqR
  • .VbgQJ
  • .vKRa
  • .vLFew
  • .vLuwMjt
  • .VQEW
  • .vVtHs
  • .wBgPqL
  • .WChzQ
  • .wHOXfI
  • .wpx
  • .XONIz
  • .XuFxtemZ
  • .xuiKKV
  • .YAKxvkvX
  • .YfZxME
  • .YgAlwFK
  • .YGFhwuZj
  • .yLnd
  • .yQBFV
  • .YSmQZYGF
  • .Zbnm
  • .zdBLY
  • .ZLom
  • .ZRDlH
  • .zUnjegnM
  • .zyucABE

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.656.02

FIRST VSAPI PATTERN DATE:

17 Oct 2024

VSAPI OPR PATTERN File:

19.657.00

VSAPI OPR PATTERN Date:

18 Oct 2024

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.XXPE50FFF088

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

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_LOCAL_MACHINE\Classes\.uQlf
    • (Default) = uQlfIcon
  • In HKEY_LOCAL_MACHINE\Classes\uQlfIcon\DefaultIcon
    • (Default) = %ProgramData%\xx.ico

Step 5

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\Classes
    • .uQlf
  • In HKEY_LOCAL_MACHINE\Classes
    • uQlfIcon

Step 6

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.
    • %ProgramData%\xx.ico
    • cmd /c %ProgramData%\1.bat
    • {Encrypted Path}\Readme.uQlf.txt

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.HELDOWN.THJAGBD. 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 8

Restore encrypted files from backup.


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