Analysis by: Raymart Christian Yambot

ALIASES:

Win32:RansomX-gen [Ransom] (AVAST)

 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 encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 25,088 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 04 Feb 2024
Payload: Drops files, Encrypts files

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 and executes the following files:

  • %Application Data%\svchost.exe → Executed with Escalated Privileges

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming 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 & wmic shadowcopy delete
  • %System%\cmd.exe" /C bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no
  • %System%\cmd.exe" /C wbadmin delete catalog -quiet
  • %System%\NOTEPAD.EXE" %Application Data%\OPEN_THIS.txt
  • %Application Data%\svchost.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Ransomware drops the following file(s) in the Windows Startup folder to enable its automatic execution at every system startup:

  • %Start Menu%\Programs\Startup\svchost.url

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Propagation

This Ransomware drops the following copy of itself in all physical and removable drives:

  • {Drive Letter}:\Sexy_porn.exe → Excluding drive C:\

Other Details

This Ransomware does the following:

  • In Drive C, it will only encrypt the following directories:
    • %User Profile%\Desktop
    • %User Profile%\Links
    • %User Profile%\Contacts
    • %User Profile%\Desktop
    • %User Profile%\Documents
    • %User Profile%\Downloads
    • %User Profile%\Pictures
    • %User Profile%\Music
    • %User Profile%\OneDrive
    • %User Profile%\Saved Games
    • %User Profile%\Favorites
    • %User Profile%\Searches
    • %User Profile%\Videos
    • %User Profile%\AppData\Roaming
    • %Public%\Documents
    • %Public%\Pictures
    • %Public%\Music
    • %Public%\Videos
    • %Public%\Desktop
  • Attempts to change desktop background using the following file:
    • %User Temp%\{Random 9 characters}.jpg

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.. %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).)

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .txt
  • .jar
  • .dat
  • .contact
  • .settings
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .mka
  • .mhtml
  • .oqy
  • .png
  • .csv
  • .py
  • .sql
  • .mdb
  • .php
  • .asp
  • .aspx
  • .html
  • .htm
  • .xml
  • .psd
  • .pdf
  • .xla
  • .cub
  • .dae
  • .indd
  • .cs
  • .mp3
  • .mp4
  • .dwg
  • .zip
  • .rar
  • .mov
  • .rtf
  • .bmp
  • .mkv
  • .avi
  • .apk
  • .lnk
  • .dib
  • .dic
  • .dif
  • .divx
  • .iso
  • .7zip
  • .ace
  • .arj
  • .bz2
  • .cab
  • .gzip
  • .lzh
  • .tar
  • .jpeg
  • .xz
  • .mpeg
  • .torrent
  • .mpg
  • .core
  • .pdb
  • .ico
  • .pas
  • .db
  • .wmv
  • .swf
  • .cer
  • .bak
  • .backup
  • .accdb
  • .bay
  • .p7c
  • .exif
  • .vss
  • .raw
  • .m4a
  • .wma
  • .flv
  • .sie
  • .sum
  • .ibank
  • .wallet
  • .css
  • .js
  • .rb
  • .crt
  • .xlsm
  • .xlsb
  • .7z
  • .cpp
  • .java
  • .jpe
  • .ini
  • .blob
  • .wps
  • .docm
  • .wav
  • .3gp
  • .webm
  • .m4v
  • .amv
  • .m4p
  • .svg
  • .ods
  • .bk
  • .vdi
  • .vmdk
  • .onepkg
  • .accde
  • .jsp
  • .json
  • .gif
  • .log
  • .gz
  • .config
  • .vb
  • .m1v
  • .sln
  • .pst
  • .obj
  • .xlam
  • .djvu
  • .inc
  • .cvs
  • .dbf
  • .tbi
  • .wpd
  • .dot
  • .dotx
  • .xltx
  • .pptm
  • .potx
  • .potm
  • .pot
  • .xlw
  • .xps
  • .xsd
  • .xsf
  • .xsl
  • .kmz
  • .accdr
  • .stm
  • .accdt
  • .ppam
  • .pps
  • .ppsm
  • .1cd
  • .3ds
  • .3fr
  • .3g2
  • .accda
  • .accdc
  • .accdw
  • .adp
  • .ai
  • .ai3
  • .ai4
  • .ai5
  • .ai6
  • .ai7
  • .ai8
  • .arw
  • .ascx
  • .asm
  • .asmx
  • .avs
  • .bin
  • .cfm
  • .dbx
  • .dcm
  • .dcr
  • .pict
  • .rgbe
  • .dwt
  • .f4v
  • .exr
  • .kwm
  • .max
  • .mda
  • .mde
  • .mdf
  • .mdw
  • .mht
  • .mpv
  • .msg
  • .myi
  • .nef
  • .odc
  • .geo
  • .swift
  • .odm
  • .odp
  • .oft
  • .orf
  • .pfx
  • .p12
  • .pl
  • .pls
  • .safe
  • .tab
  • .vbs
  • .xlk
  • .xlm
  • .xlt
  • .xltm
  • .svgz
  • .slk
  • .tar.gz
  • .dmg
  • .ps
  • .psb
  • .tif
  • .rss
  • .key
  • .vob
  • .epsp
  • .dc3
  • .iff
  • .onepkg
  • .onetoc2
  • .opt
  • .p7b
  • .pam
  • .r3d

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

  • .NOOSE

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

  • {Encrypted Directory}\OPEN_THIS.txt


  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.158.02
FIRST VSAPI PATTERN DATE: 14 Feb 2024
VSAPI OPR PATTERN File: 19.159.00
VSAPI OPR PATTERN Date: 15 Feb 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:

    • Ransom.Win32.TRX.XXPE50FFF077

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

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.  
  • %Start Menu%\Programs\Startup\svchost.url
  • {Drive Letter}:\Sexy_porn.exe
  • %User Temp%\{Random 9 characters}.jpg
  • {Encrypted Directory}\OPEN_THIS.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.PAYNOOSE.THBOEBD. 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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