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Ransom.Win32.LOCKCRYPT.EKNAK.go

December 23, 2022
 Analysis by: Jayvee Mark Villaroman
 ALIASES:

Trojan.WinGo.Rozena (IKARUS)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • 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. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

2,334,720 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

21 Dec 2022

Payload:

Encrypts files, Displays message/message boxes, Modifies system registry, 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:

  • %System Root%\Users\Public\.lock
  • %Desktop%\Readme.html
  • {Malware directory}\files.txt

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %System%\cmd.exe /c vssadmin delete shadows /all /quiet
  • %System%\wevtutil.exe cl system
  • %System%\wevtutil.exe cl security

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

Other System Modifications

This Ransomware deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client
Default = " "

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client
Servers = " "

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
WordWheelQuery = " "

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer
TypedPaths = " "

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer
RunMRU = " "

Process Termination

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

  • mysqld-opt.exe
  • dbeng50.exe
  • msftestsql.exe
  • agentsvc.exe
  • ocomm.exe
  • ocssd.exe
  • firefoxconfig.exe
  • excel.exe
  • mysql-nt.exe
  • onenote.exe
  • outlook.exe
  • tnslsnr.exe
  • oracle.exe
  • mysqld.exe
  • mydesktopservice.exe
  • thebat.exe
  • powerpnt.exe
  • visio.exe
  • infopath.exe
  • dbsnmp.exe
  • steam.exe
  • winword.exe
  • wordpad.exe
  • mspub.exe
  • synctime.exe
  • sqbcoreservice.exe
  • sqlbrowser.exe
  • thunderbird.exe
  • mysqld-nt.exe
  • tnslsnr.exe
  • mysqld.exe
  • sqlwriter.exe
  • sqlservr.exe
  • sqlagent.exe
  • msftesql.exe
  • encsvc.exe
  • isqlplussvc.exe
  • tbirdconfig.exe
  • xfssvccon.exe

Ransomware Routine

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

  • $recycle.bin
  • all users
  • appdata
  • application data
  • boot
  • config.msi
  • default
  • msocache
  • perflogs
  • program files
  • program files (x86)
  • programdata
  • public
  • system volume information
  • windows
  • windows.old

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

  • {Original Filename & file extension}.[Readme.html on Desktop}

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

  • %Desktop%\Readme.html

It avoids encrypting files with the following file extensions:

  • inf
  • bat
  • cab
  • cmd
  • com
  • cpl
  • cur
  • dll
  • drv
  • exe
  • hlp
  • hta
  • icl
  • ico
  • idx
  • ini
  • lnk
  • msi
  • ocx
  • spl
  • sys
  • [Readme.html on Desktop]

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

18.146.04

FIRST VSAPI PATTERN DATE:

21 Dec 2022

VSAPI OPR PATTERN File:

18.147.00

VSAPI OPR PATTERN Date:

22 Dec 2022

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

Restart in Safe Mode

[ Learn More ]

Step 4

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.
  • %System Root%\Users\Public\.lock
  • %Desktop%\Readme.html
  • {Malware directory}\files.txt

Step 5

Enabling Volume Shadow Service

  1. Run the command prompt (cmd.exe) as administrator.
  2. Enable Volume Shadow Service by typing the following command:
    net start vss

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.LOCKCRYPT.EKNAK.go. 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 7

Restore encrypted files from backup.

Step 8

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client
    • Default = " "
  • In HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client
    • Servers = " "
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • WordWheelQuery = " "
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
    • TypedPaths = " "
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
    • RunMRU = " "

Step 9

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.LOCKCRYPT.EKNAK.go. 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:


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