Analysis by: John Rainier Navato

ALIASES:

HEUR:Trojan-Ransom.Win32.Generic (KASPERSKY)

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 17,274 bytes
File Type: PS1
Memory Resident: No
Initial Samples Received Date: 07 Dec 2023
Payload: Drops files, Deletes 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:

  • %User Profile%\none.txt → encrypted afterwards and renamed as none.txt.greystars@protonmail
  • %Temp%\{Random 1} → contains the certificate used for encryption (deleted afterwards)
  • %Temp%\{Random 2} → contains the AES Key and IV used for encryption (deleted afterwards)

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

It adds the following processes:

  • %System%\bcdedit.exe -noninteractive /set -encodedCommand ZABlAGYAYQB1AGwAdAA= bootstatuspolicy ignoreallfailures -inputFormat xml -outputFormat xml
  • %System%\bcdedit.exe -noninteractive /set -encodedCommand ZABlAGYAYQB1AGwAdAA= recoveryenabled No -inputFormat xml -outputFormat xml
  • %System%\bcdedit.exe /set bootstatuspolicy ignoreallfailures
  • %System%\bcdedit.exe /set recoveryenabled No
  • %System%\taskkill.exe /f /im agntsvc.exe /im isqlplussvc.exe /im ncsvc.exe /im msftesql.exe /im sqlagent.exe /im sqlbrowser.exe /im sqlservr.exe /im sqlserver.exe /im sqlwriter.exe /im oracle.exe /im ocssd.exe /im dbsnmp.exe /im synctime.exe
  • %System%\vssadmin.exe Delete Shadows /All /Quiet
  • %System%\wbadmin.exe DELETE SYSTEMSTATEBACKUP -keepVersions:0
  • %System%\Wbem\WMIC.exe SHADOWCOPY DELETE
  • %System%\wevutil.exe cl "windows powershell"
  • %System%\wevutil.exe cl security
  • %System%\wevutil.exe cl system

(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 adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\SystemRestore
DisableSR = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
ShellServiceObjects\{FD6905CE-952F-41F1-9A6F-135D9C6622CC}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WindowsDefender =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
StartupApproved\Run
WindowsDefender =

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WindowsDefender =

Process Termination

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

  • agntsvc.exe
  • dbeng50.exe
  • dbsnmp.exe
  • encsvc.exe
  • firefoxconfig.exe
  • isqlplussvc.exe
  • isqlplussvc.exe
  • msftesql.exe
  • mydesktopqos.exe
  • mydesktopservice.exe
  • mysqld-nt.exe
  • mysqld-opt.exe
  • mysqld.exe
  • ncsvc.exe
  • ocautoupds.exe
  • ocomm.exe
  • ocssd.exe
  • oracle.exe
  • oracle.exe
  • sqbcoreservice.exe
  • sql.exe
  • sqlagent.exe
  • sqlbrowser.exe
  • sqlite.exe
  • sqlserver.exe
  • sqlservr.exe
  • sqlwriter.exe
  • synctime.exe;
  • tbirdconfig.exe
  • xfssvccon.exe

Other Details

This Ransomware does the following:

  • It terminates the following services:
    • BITS
    • ERSvc
    • vss
    • WerSvc
    • WinDefend
    • Wscsvc
    • Wuauserv
  • It terminates itself if %User Profile%\none.txt.greystars@protonmail already exists.
  • It encrypts files on fixed drives except in C: wherein it encrypts only the following:
    • %User Profile%\Desktop
    • %User Profile%\Documents
  • It clears the Windows PowerShell, Security, and System event logs.
  • It force restart the system after encrypting files.
  • It displays log activity through console.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .1cd
  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .3pr
  • .602
  • .7z
  • .7zip
  • .aac
  • .ab4
  • .accdb
  • .accde
  • .accdr
  • .accdt
  • .ach
  • .acr
  • .act
  • .adb
  • .adp
  • .ads
  • .aes
  • .agdl
  • .ai
  • .aiff
  • .ait
  • .al
  • .aoi
  • .apj
  • .arc
  • .arw
  • .asc
  • .asf
  • .asm
  • .asp
  • .aspx
  • .asx
  • .avi
  • .awg
  • .back
  • .backup
  • .backupdb
  • .bak
  • .bank
  • .bat
  • .bay
  • .bdb
  • .bgt
  • .bik
  • .bin
  • .bkp
  • .blend
  • .bmp
  • .bpw
  • .brd
  • .c
  • .cdf
  • .cdr
  • .cdr3
  • .cdr4
  • .cdr5
  • .cdr6
  • .cdrw
  • .cdx
  • .ce1
  • .ce2
  • .cer
  • .cfg
  • .cgm
  • .cib
  • .class
  • .cls
  • .cmd
  • .cmt
  • .config
  • .contact
  • .cpi
  • .cpp
  • .cr2
  • .craw
  • .crt
  • .crw
  • .cs
  • .csh
  • .csl
  • .csr
  • .css
  • .csv
  • .dac
  • .dat
  • .db
  • .db3
  • .db_journal
  • .dbf
  • .dbx
  • .dc2
  • .dch
  • .dcr
  • .dcs
  • .ddd
  • .ddoc
  • .ddrw
  • .dds
  • .der
  • .des
  • .design
  • .dgc
  • .dif
  • .dip
  • .dit
  • .djv
  • .djvu
  • .dll
  • .dng
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .drf
  • .drw
  • .dtd
  • .dwg
  • .dxb
  • .dxf
  • .dxg
  • .edb
  • .eml
  • .eps
  • .erbsql
  • .erf
  • .exf
  • .fdb
  • .ffd
  • .fff
  • .fh
  • .fhd
  • .fla
  • .flac
  • .flf
  • .flv
  • .flvv
  • .fpx
  • .frm
  • .fxg
  • .gif
  • .gpg
  • .gray
  • .grey
  • .groups
  • .gry
  • .gz
  • .h
  • .hbk
  • .hdd
  • .hpp
  • .html
  • .hwp
  • .ibank
  • .ibd
  • .ibz
  • .idx
  • .iif
  • .iiq
  • .incpas
  • .indd
  • .jar
  • .java
  • .jnt
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .kc2
  • .kdbx
  • .kdc
  • .key
  • .kpdx
  • .kwm
  • .laccdb
  • .lay
  • .lay6
  • .ldf
  • .lit
  • .log
  • .lua
  • .m
  • .m2ts
  • .m3u
  • .m4p
  • .m4u
  • .m4v
  • .mapimail
  • .max
  • .mbx
  • .md
  • .mdb
  • .mdc
  • .mdf
  • .mef
  • .mfw
  • .mid
  • .mkv
  • .mlb
  • .mml
  • .mmw
  • .mny
  • .moneywell
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mrw
  • .ms11
  • .msg
  • .myd
  • .myi
  • .nd
  • .ndd
  • .ndf
  • .nef
  • .nk2
  • .nop
  • .nrw
  • .ns2
  • .ns3
  • .ns4
  • .nsd
  • .nsf
  • .nsg
  • .nsh
  • .nvram
  • .nwb
  • .nx2
  • .nxl
  • .nyf
  • .oab
  • .obj
  • .odb
  • .odc
  • .odf
  • .odg
  • .odm
  • .odp
  • .ods
  • .odt
  • .ogg
  • .oil
  • .orf
  • .ost
  • .otg
  • .oth
  • .otp
  • .ots
  • .ott
  • .p12
  • .p7b
  • .p7c
  • .pab
  • .pages
  • .paq
  • .pas
  • .pat
  • .pcd
  • .pct
  • .pdb
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .pif
  • .pl
  • .plc
  • .plus_muhd
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .ps
  • .ps1
  • .psafe3
  • .psd
  • .pspimage
  • .pst
  • .ptx
  • .pwm
  • .py
  • .qba
  • .qbb
  • .qbm
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .qcow
  • .qcow2
  • .qed
  • .r3d
  • .raf
  • .rar
  • .rat
  • .raw
  • .rb
  • .rdb
  • .rm
  • .rtf
  • .rvt
  • .rw2
  • .rwl
  • .rwz
  • .s3db
  • .safe
  • .sas7bdat
  • .sav
  • .save
  • .say
  • .sch
  • .sd0
  • .sda
  • .sdf
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .sql
  • .sqlite
  • .sqlite3
  • .sqlitedb
  • .sr2
  • .srf
  • .srt
  • .srw
  • .st4
  • .st5
  • .st6
  • .st7
  • .st8
  • .stc
  • .std
  • .sti
  • .stm
  • .stw
  • .stx
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxg
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tar.bz2
  • .tbk
  • .tex
  • .tga
  • .tgz
  • .thm
  • .tif
  • .tiff
  • .tlg
  • .txt
  • .uop
  • .uot
  • .vb
  • .vbox
  • .vbs
  • .vdi
  • .vhd
  • .vhdx
  • .vmdk
  • .vmsd
  • .vmx
  • .vmxf
  • .vob
  • .wab
  • .wad
  • .wallet
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .x11
  • .x3f
  • .xis
  • .xla
  • .xlam
  • .xlc
  • .xlk
  • .xlm
  • .xlr
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .ycbcra
  • .yuv
  • .zip

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

  • How-To-Recover

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

  • .greystars@protonmail

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

  • {Encrypted Path}\How-To-Recover-Your-Files.html

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.874.04
FIRST VSAPI PATTERN DATE: 12 Dec 2023
VSAPI OPR PATTERN File: 18.875.00
VSAPI OPR PATTERN Date: 13 Dec 2023

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

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\SOFTWARE\Microsoft\Windows\CurrentVersion\SystemRestore
    • DisableSR
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
    • DisableAntiSpyware

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellServiceObjects
    • {FD6905CE-952F-41F1-9A6F-135D9C6622CC}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • WindowsDefender
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\StartupApproved\Run
    • WindowsDefender
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • WindowsDefender

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.  
  • %User Profile%\none.txt.greystars@protonmail
  • %Temp%\{Random 1}
  • %Temp%\{Random 2}
  • {Encrypted Path}\How-To-Recover-Your-Files.html

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.PS1.SRATSYERG.THLOGBC. 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.

NOTES:

Do this as Step 8 of the solution process:

Enable Windows Recovery Option and Enable Firewall

  1. Run cmd.exe as administrator
  2. Type "bcdedit /set {default} recoveryenabled Yes" then press Enter
  3. Type "bcdedit /set {default} bootstatuspolicy displayallfailures" then press Enter.


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