Analysis by: Khristian Joseph Morales
ALIASES:

Ransom:Win32/Yanluow.A (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

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: 398,848 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 03 Dec 2021
Payload: Drops 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 adds the following processes:

  • Terminate running virtual machines
    • "/c powershell -command \"Get-VM | Stop-VM -Force\""
  • Terminate Services
    • %System%\cmd.exe net stop MSSQLServerADHelper100
    • %System%\cmd.exe net stop MSSQL$ISARS
    • %System%\cmd.exe net stop MSSQL$MSFW
    • %System%\cmd.exe net stop SQLAgent$ISARS
    • %System%\cmd.exe net stop SQLAgent$MSFW
    • %System%\cmd.exe net stop SQLBrowser
    • %System%\cmd.exe net stop ReportServer$ISARS
    • %System%\cmd.exe net stop SQLWriter
    • %System%\cmd.exe net stop WinDefend
    • %System%\cmd.exe net stop mr2kserv
    • %System%\cmd.exe net stop MSExchangeADTopology
    • %System%\cmd.exe net stop MSExchangeFBA
    • %System%\cmd.exe net stop MSExchangeIS
    • %System%\cmd.exe net stop MSExchangeSA
    • %System%\cmd.exe net stop ShadowProtectSvc
    • %System%\cmd.exe net stop SPAdminV4
    • %System%\cmd.exe net stop SPTimerV4
    • %System%\cmd.exe net stop SPTraceV4
    • %System%\cmd.exe net stop SPUserCodeV4
    • %System%\cmd.exe net stop SPWriterV4
    • %System%\cmd.exe net stop SPSearch4
    • %System%\cmd.exe net stop MSSQLServerADHelper100
    • %System%\cmd.exe net stop IISADMIN
    • %System%\cmd.exe net stop firebirdguardiandefaultinstance
    • %System%\cmd.exe net stop ibmiasrw
    • %System%\cmd.exe net stop QBCFMonitorService
    • %System%\cmd.exe net stop QBVSS
    • %System%\cmd.exe net stop QBPOSDBServiceV12
    • %System%\cmd.exe net stop "IBM Domino Server (CProgramFilesIBMDominodata)"
    • %System%\cmd.exe net stop "IBM Domino Diagnostics (CProgramFilesIBMDomino)"
    • %System%\cmd.exe net stop IISADMIN
    • %System%\cmd.exe net stop "Simply Accounting Database Connection Manager"
    • %System%\cmd.exe net stop QuickBooksDB1
    • %System%\cmd.exe net stop QuickBooksDB2
    • %System%\cmd.exe net stop QuickBooksDB3
    • %System%\cmd.exe net stop QuickBooksDB4
    • %System%\cmd.exe net stop QuickBooksDB5
    • %System%\cmd.exe net stop QuickBooksDB6
    • %System%\cmd.exe net stop QuickBooksDB7
    • %System%\cmd.exe net stop QuickBooksDB8
    • %System%\cmd.exe net stop QuickBooksDB9
    • %System%\cmd.exe net stop QuickBooksDB10
    • %System%\cmd.exe net stop QuickBooksDB11
    • %System%\cmd.exe net stop QuickBooksDB12
    • %System%\cmd.exe net stop QuickBooksDB13
    • %System%\cmd.exe net stop QuickBooksDB14
    • %System%\cmd.exe net stop QuickBooksDB15
    • %System%\cmd.exe net stop QuickBooksDB16
    • %System%\cmd.exe net stop QuickBooksDB17
    • %System%\cmd.exe net stop QuickBooksDB18
    • %System%\cmd.exe net stop QuickBooksDB19
    • %System%\cmd.exe net stop QuickBooksDB20
    • %System%\cmd.exe net stop QuickBooksDB21
    • %System%\cmd.exe net stop QuickBooksDB22
    • %System%\cmd.exe net stop QuickBooksDB23
    • %System%\cmd.exe net stop QuickBooksDB24
    • %System%\cmd.exe net stop QuickBooksDB25
  • Display ransomnote
    • %System%\cmd.exe /c for /l %x in (1,1,3) do start wordpad.exe /p {Malware Directory}\README.txt

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

Process Termination

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

  • Terminate Process that matches the following string:
    • mysql*
    • dsa*
    • veeam*
    • chrome*
    • iexplore*
    • firefox*
    • outlook*
    • excel*
    • outlook*
    • taskmgr*
    • tasklist*
    • Ntrtscan*
    • ds_monitor*
    • Notifier*
    • putty*
    • ssh*
    • TmListen*
    • iVPAgent*
    • CNTAoSMgr*
    • IBM*
    • bes10*
    • black*
    • robo*
    • copy*
    • sql
    • store.exe
    • sql*
    • vee*
    • wrsa*
    • wrsa.exe
    • postg*

Other Details

This Ransomware does the following:

  • It requires the following password to execute
    • D86BDXL9N3H
  • It encrypts the files in the specified directory

It accepts the following parameters:

  • -h / --help
  • -p / -path / --path
  • -pass

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • .yanluowang

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

  • {Encrypted Directory}\README.txt
  • {Malware Directory}\README.txt

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 17.232.05
FIRST VSAPI PATTERN DATE: 04 Dec 2021
VSAPI OPR PATTERN File: 17.233.00
VSAPI OPR PATTERN Date: 05 Dec 2021

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.XXPE50FFF051

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

Identify and terminate files detected as Ransom.Win32.YANLUOWANG.THLOCBA

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 5

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.
  • {Encrypted Directory}\README.txt
  • {Malware Directory}\README.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.YANLUOWANG.THLOCBA. 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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