Analysis by: Neljorn Nathaniel Aguas

ALIASES:

MSIL/ClipBanker.SX!tr (FORTINET)

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

  TECHNICAL DETAILS

File Size: 240,672 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 27 Dec 2023
Payload: Drops files, Displays graphics/image, 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 the following files:

  • %User Temp%\{9 Random Characters}.jpg → plain white image used to set the Desktop's wallpaper.

(Note: %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).)

It drops and executes the following files:

  • %Application Data%\svchost.exe → drops and executes only if {Malware Path}\{Malware Filename} is not equal to it.

(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 → deletes all volume shadow copies in the system.
  • "%System%\cmd.exe" /C bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no → disables Windows RE error recovery, and automatic restart.
  • "%System%\cmd.exe" /C wbadmin delete catalog -quiet → deletes the backup catalog on the system.
  • "%System%\NOTEPAD.EXE" %Application Data%\read_it.txt → opens the dropped ransom note.

(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 User Startup folder to enable its automatic execution at every system startup:

  • Filename: %User Startup%\svchost.url
    URL: file:///%Application Data%\svchost.exe

(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).)

Other System Modifications

This Ransomware changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\{9 Random Characters}.jpg

(Note: The default value data of the said registry entry is {Default Image Filename}.)

It sets the system's desktop wallpaper to the following image:

Propagation

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

  • {Drive Letter}\surprise.exe → dropped in every active drive except C:.

Other Details

This Ransomware does the following:

  • During encryption:
    • If the file's size is less than 2,117,152 bytes, it rewrites the file's data using the following format:
      • {Encrypted Key}{Encrypted Data}
    • Otherwise, it rewrites the file's data using the following format:
      • {Encrypted Key}{Encrypted Data}
  • It utilizes Bitcoin address clipboard hijacking by checking the clipboard if it contains a Bech32 BTC address and replaces it with the following BTC address:
    • {BLOCKED}ll8p9m8uezhqhyd7z459ajrk722yn8c5j4fg

Ransomware Routine

This Ransomware encrypts files with the following extensions:

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

It encrypts files found in the following folders:

  • {Active Drives}
  • %Desktop%
  • %Favorites%
  • %Application Data%
  • %Public%\Documents
  • %Public%\Pictures
  • %Public%\Music
  • %Public%\Videos
  • %Public%\Desktop
  • %User Profile%\Links
  • %User Profile%\Contacts
  • %User Profile%\Documents
  • %User Profile%\Downloads
  • %User Profile%\Pictures
  • %User Profile%\Music
  • %User Profile%\OneDrive
  • %User Profile%\Saved Games
  • %User Profile%\Searches
  • %User Profile%\Videos

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

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

  • read_it.txt

It avoids encrypting files found in the following folders:

  • C:\

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

  • .encrypt

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

  • {Path to Encrypt}\read_it.txt
  • %Application Data%\read_it.txt → opened afterwards

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.116.03
FIRST VSAPI PATTERN DATE: 24 Jan 2024
VSAPI OPR PATTERN File: 19.117.00
VSAPI OPR PATTERN Date: 25 Jan 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:

     
    • TSPY.Win32.TRX.XXPE50FFF076

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

Restart in Safe Mode

[ Learn More ]

Step 5

Restore this modified 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_CURRENT_USER\Control Panel\Desktop
    • Wallpaper = %User Temp%\{9 Random Characters}.jpg

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.
  • %Application Data%\svchost.exe
  • %User Startup%\svchost.url
  • {Drive Letter}\surprise.exe
  • {Encrypted Path}\read_it.txt
  • %Application Data%\read_it.txt
  • %User Temp%\{9 Random Characters}.jpg

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.MSIL.CHAOS.I. 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 8

Restore encrypted files from backup.

Step 9

Reset your Desktop properties

[ Learn More ]


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