Analysis by: John Rey Canon
ALIASES:

MSIL/Filecoder.QU!tr (Fortinet)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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 is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 166,912 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 28 Jan 2019
Payload: Displays graphics/image, Displays message/message boxes, Connects to URLs/IPs, 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 adds the following processes:

  • "cmd.exe" /c vssadmin.exe delete shadows /all /quiet

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

  • check

Other System Modifications

This Ransomware sets the system's desktop wallpaper to the following image:

Other Details

This Ransomware does the following:

  • It displays the following window after encrypting files:
  • It drops the following file(s) as ransom note:
    • {Drive Letter}:\#DECRYPT MY FILES#.HTML
    • {Drive Letter}:\#解密我的文件#.HTML
    • {Drive Letter}:\#내 파일 복구하기#.HTML
    • %Desktop%\#DECRYPT MY FILES#.HTML
    • %Desktop%\#解密我的文件#.HTML
    • %Desktop%\#내 파일 복구하기#.HTML
  • The ransom note contains the following:
  • It creates the following registry entries in order to display its ransom note every time the Windows startup:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
    Windows NT\CurrentVersion\Winlogon
    LegalNoticeCaption = "All your important
    files are encrypted!"

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
    Windows NT\CurrentVersion\Winlogon
    LegalNoticeText = "{Contents are same
    as ransom notes}"


  • It accessed the shortened URL https://{BLOCKED}er.org/2nZ7w5 that leads to https://i.{BLOCKED}i.net/2019/01/24/5c49d7ec69126.png, an online image hosting site.
  • It downloads an image file from an online image hosting site.
    • URL: https://i.{BLOCKED}i.net/2019/01/24/5c49d80a2b878.bmp
    • Filename: %Desktop%\WALLPAPER.BMP
  • It uses speech synthesis and says the following:
    • Attention! Your documents, images, databases and other important files have been encrypted!

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .1cd
  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3pr
  • .7z
  • .7zip
  • .aac
  • .ab4
  • .accdb
  • .accde
  • .accdr
  • .accdt
  • .ach
  • .acr
  • .act
  • .adb
  • .adp
  • .advertisements
  • .agdl
  • .ai
  • .ait
  • .al
  • .aoi
  • .ape
  • .apj
  • .apk
  • .arc
  • .arw
  • .asf
  • .asm
  • .asp
  • .aspx
  • .asx
  • .avi
  • .awg
  • .back
  • .backup
  • .backupdb
  • .bak
  • .bat
  • .bay
  • .bdb
  • .bgt
  • .bik
  • .bpw
  • .c
  • .c4d
  • .cdr
  • .cdr3
  • .cdr4
  • .cdr5
  • .cdr6
  • .cdrw
  • .ce1
  • .ce2
  • .cer
  • .cfg
  • .cib
  • .class
  • .cls
  • .cmd
  • .conf
  • .config
  • .contact
  • .cpi
  • .cpp
  • .craw
  • .crw
  • .cs
  • .csh
  • .csl
  • .css
  • .csv
  • .db
  • .db3
  • .dbx
  • .db_journal
  • .dc2
  • .dcs
  • .ddoc
  • .ddrw
  • .dds
  • .der
  • .des
  • .dgc
  • .dip
  • .djvu
  • .dng
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .drf
  • .drw
  • .dwg
  • .dxb
  • .dxf
  • .dxg
  • .eml
  • .eps
  • .epub
  • .erbsql
  • .erf
  • .exf
  • .ffd
  • .fh
  • .fhd
  • .fla
  • .flac
  • .flf
  • .flp
  • .flv
  • .frm
  • .fxg
  • .gif
  • .gpg
  • .gray
  • .grey
  • .groups
  • .gry
  • .hbk
  • .hdd
  • .hpp
  • .html
  • .ibd
  • .ibz
  • .idx
  • .iiq
  • .incpas
  • .jar
  • .java
  • .jnt
  • .jpe
  • .jpg
  • .js
  • .jsp
  • .jtp
  • .kc2
  • .kdbx
  • .kdc
  • .key
  • .kpdx
  • .kwm
  • .laccdb
  • .lay
  • .lay6
  • .ldf
  • .lit
  • .log
  • .lua
  • .m
  • .m2ts
  • .m3u
  • .m4p
  • .m4u
  • .m4v
  • .max
  • .mbx
  • .md
  • .mdb
  • .mdc
  • .mdf
  • .mef
  • .mfw
  • .mid
  • .mkv
  • .mlb
  • .mml
  • .mmw
  • .mny
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mrw
  • .msg
  • .myd
  • .myi
  • .ndd
  • .ndf
  • .nef
  • .nk2
  • .nop
  • .nrw
  • .ns2
  • .ns3
  • .ns4
  • .nvram
  • .nwb
  • .nx2
  • .nxl
  • .nyf
  • .oab
  • .obj
  • .odb
  • .odf
  • .odg
  • .odm
  • .ods
  • .odt
  • .ogg
  • .oil
  • .onetoc2
  • .orf
  • .ost
  • .otg
  • .oth
  • .otp
  • .ots
  • .ott
  • .p12
  • .p7b
  • .p7c
  • .pab
  • .pages
  • .paq
  • .pcd
  • .pct
  • .pdb
  • .pdd
  • .pdf
  • .pem
  • .php
  • .pif
  • .pl
  • .plc
  • .plus_muhd
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .ps
  • .ps1
  • .psafe3
  • .psd
  • .pst
  • .pwm
  • .py
  • .qba
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .qcow
  • .qcow2
  • .qed
  • .r3d
  • .raf
  • .rar
  • .rat
  • .raw
  • .rdb
  • .rm
  • .rtf
  • .rvt
  • .rw2
  • .rwl
  • .rwz
  • .s3db
  • .safe
  • .sav
  • .save
  • .sch
  • .sd0
  • .sda
  • .sdf
  • .sldm
  • .sldx
  • .slk
  • .sln
  • .snt
  • .sql
  • .sqlite
  • .sqlite3
  • .sqlitedb
  • .sr2
  • .srf
  • .srt
  • .srw
  • .st5
  • .st7
  • .st8
  • .std
  • .sti
  • .stm
  • .stx
  • .suo
  • .svg
  • .swf
  • .sxd
  • .sxg
  • .sxi
  • .sxm
  • .sxw
  • .tex
  • .tga
  • .tgz
  • .thm
  • .tif
  • .tiff
  • .txt
  • .uop
  • .uot
  • .vb
  • .vbox
  • .vbs
  • .vcd
  • .vdi
  • .vhd
  • .vhdx
  • .vip
  • .vmdk
  • .vmsd
  • .vmx
  • .vmxf
  • .vob
  • .wab
  • .wallet
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .x11
  • .x3f
  • .xis
  • .xla
  • .xlam
  • .xlc
  • .xlm
  • .xlr
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .ycbcra
  • .yuv
  • .zip

It encrypts files found in the following folders:

  • {Drive Letter}:\
  • %ProgramData%
  • %Favorites%
  • %User Profile%\Documents
  • %User Profile%\Pictures
  • %User Profile%\Music
  • %AppDataLocal%\Microsoft\Windows\History
  • %User Profile%\Downloads
  • %User Profile%\Videos
  • %Desktop%

(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.. %Favorites% is the current user's Favorites folder, which is usually C:\Documents and Settings\{user name}\Favorites on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Favorites on 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, XP, and Server 2003, or C:\Users\{user name} on Windows Vista, 7, and 8.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.)

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

  • .[buy-decryptor@{BLOCKED}m.me]

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.778.02
FIRST VSAPI PATTERN DATE: 28 Jan 2019
VSAPI OPR PATTERN File: 14.779.00
VSAPI OPR PATTERN Date: 29 Jan 2019

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

Identify and terminate files detected as Ransom.Win32.GORGON.THOABHAI

[ 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 4

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 NT\CurrentVersion\Winlogon
    • LegalNoticeCaption = "All your important files are encrypted!"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • LegalNoticeText = "{Contents are same as ransom notes}"

Step 5

Search and delete this file

[ 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.
  • {Drive Letter}:\#DECRYPT MY FILES#.HTML
  • {Drive Letter}:\#解密我的文件#.HTML
  • {Drive Letter}:\#내 파일 복구하기#.HTML
  • %Desktop%\#DECRYPT MY FILES#.HTML
  • %Desktop%\#解密我的文件#.HTML
  • %Desktop%\#내 파일 복구하기#.HTML
  • %Desktop%\WALLPAPER.BMP

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.GORGON.THOABHAI. 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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