Analysis by: Joshua Paul Ignacio
ALIASES:

Ransom:Win32/Wadhrama!hoa (MICROSOFT); Trojan-Ransom.Win32.Crusis.to (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 may be dropped by other malware.

It enables its automatic execution at every system startup by dropping copies of itself into the Windows Common Startup folder.

It terminates processes found running in the affected device.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 94,720 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 Mar 2021
Payload: Displays graphics/image, Displays message/message boxes, 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.

It may be dropped by the following malware:

Installation

This Ransomware drops the following copies of itself into the affected system:

  • %System%\winhost.exe

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

It adds the following processes:

  • mode con cp select=1251
  • vssadmin delete shadows /all /quiet → Deletes shadow copies
  • "%System%\mshta.exe" %User Startup%\Info.hta"
  • "%System%\mshta.exe" "%Common Startup%\Info.hta"

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).. %Common Startup% is the startup folder for all users, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003, or C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\syncronize_K0DI1RA
  • Global\syncronize_K0DI1RU

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
winhost.exe = %System%\winhost.exe

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
%Application Data%\Info.hta = mshta.exe "%Application Data%\Info.hta"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
%System%\Info.hta = mshta.exe "%System%\Info.hta"

It enables its automatic execution at every system startup by dropping the following copies of itself into the Windows Common Startup folder:

  • %Common Startup%\winhost.exe

(Note: %Common Startup% is the startup folder for all users, which is usually C:\Documents and Settings\All Users\Start Menu\Programs\Startup on Windows 2000, XP, and Server 2003, or C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

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

  • %User Startup%\winhost.exe → copy of itself

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

File Infection

This Ransomware avoids infecting the following files:

  • boot.ini
  • bootfont.bin
  • Info.hta
  • io.sys
  • ntdetect.com
  • ntldr
  • RETURN FILES.txt
  • winhost.exe

Process Termination

This Ransomware terminates the following services if found on the affected system:

  • FirebirdGuardianDefaultInstance
  • FirebirdServerDefaultInstance
  • mssqlserver
  • sqlserveradhelper
  • sqlwriter

Other Details

This Ransomware encrypts files with the following extensions:

  • .1cd
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .7z
  • .accda
  • .accdb
  • .accdc
  • .accde
  • .accdt
  • .accdw
  • .adb
  • .adp
  • .ai
  • .ai3
  • .ai4
  • .ai5
  • .ai6
  • .ai7
  • .ai8
  • .anim
  • .arw
  • .as
  • .asa
  • .asc
  • .ascx
  • .asm
  • .asmx
  • .asp
  • .aspx
  • .asr
  • .asx
  • .avi
  • .avs
  • .backup
  • .bak
  • .bay
  • .bd
  • .bin
  • .bmp
  • .bz2
  • .c
  • .cdr
  • .cer
  • .cf
  • .cfc
  • .cfm
  • .cfml
  • .cfu
  • .chm
  • .cin
  • .class
  • .clx
  • .config
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .cs
  • .css
  • .csv
  • .cub
  • .dae
  • .dat
  • .db
  • .dbf
  • .dbx
  • .dc3
  • .dcm
  • .dcr
  • .der
  • .dib
  • .dic
  • .dif
  • .divx
  • .djvu
  • .dng
  • .doc
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dpx
  • .dqy
  • .dsn
  • .dt
  • .dtd
  • .dwg
  • .dwt
  • .dx
  • .dxf
  • .edml
  • .efd
  • .elf
  • .emf
  • .emz
  • .epf
  • .eps
  • .epsf
  • .epsp
  • .erf
  • .exe
  • .exr
  • .f4v
  • .fido
  • .flm
  • .flv
  • .frm
  • .fxg
  • .geo
  • .gif
  • .grs
  • .gz
  • .h
  • .hdr
  • .hpp
  • .hta
  • .htc
  • .htm
  • .html
  • .icb
  • .ics
  • .iff
  • .inc
  • .indd
  • .ini
  • .iqy
  • .j2c
  • .j2k
  • .java
  • .jp2
  • .jpc
  • .jpe
  • .jpeg
  • .jpf
  • .jpg
  • .jpx
  • .js
  • .jsf
  • .json
  • .jsp
  • .kdc
  • .kmz
  • .kwm
  • .lasso
  • .lbi
  • .lgf
  • .lgp
  • .log
  • .m1v
  • .m4a
  • .m4v
  • .max
  • .md
  • .mda
  • .mdb
  • .mde
  • .mdf
  • .mdw
  • .mef
  • .mft
  • .mfw
  • .mht
  • .mhtml
  • .mka
  • .mkidx
  • .mkv
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mpv
  • .mrw
  • .msg
  • .mxl
  • .myd
  • .myi
  • .nef
  • .nrw
  • .obj
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .oft
  • .one
  • .onepkg
  • .onetoc2
  • .opt
  • .oqy
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pam
  • .pbm
  • .pct
  • .pcx
  • .pdd
  • .pdf
  • .pdp
  • .pef
  • .pem
  • .pff
  • .pfm
  • .pfx
  • .pgm
  • .php
  • .php3
  • .php4
  • .php5
  • .phtml
  • .pict
  • .pl
  • .pls
  • .pm
  • .png
  • .pnm
  • .pot
  • .potm
  • .potx
  • .ppa
  • .ppam
  • .ppm
  • .pps
  • .ppsm
  • .ppt
  • .pptm
  • .pptx
  • .prn
  • .ps
  • .psb
  • .psd
  • .pst
  • .ptx
  • .pub
  • .pwm
  • .pxr
  • .py
  • .qt
  • .r3d
  • .raf
  • .rar
  • .raw
  • .rdf
  • .rgbe
  • .rle
  • .rqy
  • .rss
  • .rtf
  • .rw2
  • .rwl
  • .safe
  • .sct
  • .sdpx
  • .shtm
  • .shtml
  • .slk
  • .sln
  • .sql
  • .sr2
  • .srf
  • .srw
  • .ssi
  • .st
  • .stm
  • .svg
  • .svgz
  • .swf
  • .tab
  • .tar
  • .tbb
  • .tbi
  • .tbk
  • .tdi
  • .tga
  • .thmx
  • .tif
  • .tiff
  • .tld
  • .torrent
  • .tpl
  • .txt
  • .u3d
  • .udl
  • .uxdc
  • .vb
  • .vbs
  • .vcs
  • .vda
  • .vdr
  • .vdw
  • .vdx
  • .vrp
  • .vsd
  • .vss
  • .vst
  • .vsw
  • .vsx
  • .vtm
  • .vtml
  • .vtx
  • .wav
  • .wb2
  • .wbm
  • .wbmp
  • .wim
  • .wmf
  • .wml
  • .wmv
  • .wpd
  • .wps
  • .x3f
  • .xl
  • .xla
  • .xlam
  • .xlk
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xps
  • .xsd
  • .xsf
  • .xsl
  • .xslt
  • .xsn
  • .xtp
  • .xtp2
  • .xyze
  • .xz
  • .zip

It does the following:

  • It encrypts files in all fixed, remote and removable drives.

Mobile Malware Routine

This Ransomware terminates the following processes if found running on the affected device:

  • 1c8.exe
  • 1cv77.exe
  • mysqld-nt.exe
  • mysqld.exe
  • outlook.exe
  • postgres.exe
  • sqlservr.exe

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • %Windows%

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

It renames encrypted files using the following names:

  • {Original Filename}.{Original File Extension}.id-{System Volume Information}.[{BLOCKED}ypt@proton.com].bat

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

  • %User Startup%\Info.hta
  • %Common Startup%\Info.hta
  • %System%\Info.hta
  • %Application Data%\Info.hta

It leaves text files that serve as ransom notes containing the following text:

  • %Desktop%\RETURN FILES.txt
  • %Public%\Desktop\RETURN FILES.txt
  • {Drive Letter}:\RETURN FILES.txt

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.582.05
FIRST VSAPI PATTERN DATE: 08 Mar 2021
VSAPI OPR PATTERN File: 16.583.00
VSAPI OPR PATTERN Date: 09 Mar 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.XXPE50FFF042

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

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\Run
    • winhost.exe = %System%\winhost.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • %Application Data%\Info.hta = mshta.exe "%Application Data%\Info.hta"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • %System%\Info.hta = mshta.exe "%System%\Info.hta"

Step 6

Search and delete these files

[ Learn More ]
There may be some component 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%\winhost.exe
  • %User Startup%\winhost.exe
  • %Common Startup%\winhost.exe
  • %Desktop%\RETURN FILES.txt
  • %Public%\Desktop\RETURN FILES.txt
  • {Drive Letter}:\RETURN FILES.txt
  • %User Startup%\Info.hta
  • %Common Startup%\Info.hta
  • %System%\Info.hta
  • %Application Data%\Info.hta

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.CRYSIS.J. 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.


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