RANSOM.MSIL.LIGMA.THIAOAH

December 12, 2018
 Analysis by: Patrick Angelo Roderno
 ALIASES:

HEUR:Trojan.MSIL.Diztakun.gen (Kaspersky); W32/Diztakun.CJEV!tr (Fortinet); Trojan:Win32/Tiggre!rfn (Microsoft)

 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:

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

  TECHNICAL DETAILS

File Size:

57344 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 Sep 2018

Payload:

Displays message/message boxes, Encrypts files, Compromises system security

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:

  • C:\WinWOW32\work.bat
  • C:\WinWOW32\icon.ico
  • C:\WinWOW32\mbr.bin
  • C:\WinWOW32\Payloads.dll -> contains most of ransomware's additional features and functionalities

It adds the following processes:

  • cmd C:\WinWOW32\work.bat
  • takeown /f logonui.exe
  • icacls logonui.exe /granted %username%:F
  • takeown /f "C:\Windows\System32\en-US" /r /d y
  • icacls "C:\Windows\System32\en-US" /granted %username%:F /T /C
  • cd\&cd Windows
  • takeown /f explorer.exe
  • takeown /f regedit.exe
  • takeown /f HelpPane.exe
  • takeown /f "C:\Windows\Temp" /r /d y
  • takeown /f "C:\Windows\en-US" /r /d y
  • icacls "C:\Windows\Temp" /granted %username%:F /T /C
  • icacls "C:\Windows\en-US" /granted %username%:F /T /C
  • icacls regedit.exe /granted %username%:F
  • icacls explorer.exe /granted %username%:F
  • icacls HelpPane.exe /granted %username%:F
  • NetSh Advfirewall set allprofiles state off
  • vssadmin delete shadows /all /quiet
  • taskkill /f /im explorer.exe
  • start explorer.exe

It creates the following folders:

  • C:\WinWOW32

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDesktop = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
DisableTaskMgr = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
DisableCMD = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoControlPanel = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
HideClock = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoLogoff = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoWindowsUpdate = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoDrives = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
MobilityCenter
NoMobilityCenter = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = 1

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
System
DisableRegistryTools = 1

It modifies the following registry entries:

HKEY_CLASSES_ROOT\txtfile\DefaultIcon
(Default) = C:\WinWOW32\icon.ico

(Note: The default value data of the said registry entry is %System Root%\system32\imageres.dll, -102.)

HKEY_CLASSES_ROOT\exefile\DefaultIcon
(Default) = C:\WinWOW32\icon.ico

(Note: The default value data of the said registry entry is %1.)

HKEY_CLASSES_ROOT\VBSfile\DefaultIcon
(Default) = C:\WinWOW32\icon.ico

(Note: The default value data of the said registry entry is %System Root%\System32\WScript.exe, 2.)

HKEY_CLASSES_ROOT\batfile\DefaultIcon
(Default) = C:\WinWOW32\icon.ico

(Note: The default value data of the said registry entry is %System Root%\System32\imageres.dll, -68.)

HKEY_CLASSES_ROOT\dllfile\DefaultIcon
(Default) = C:\WinWOW32\icon.ico

(Note: The default value data of the said registry entry is imageres.dll, -67.)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
AutoRestartShell = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows Defender
DisableAntiSpyware = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = 0

(Note: The default value data of the said registry entry is 5.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
legalnoticecaption = LIGMA

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
legalnoticetext = Your Computer Got FUCKED By LIGMA!

Other Details

This Ransomware does the following:

  • Does not work on Windows 10, 8 and 8.1
  • Displays the following message box to confirm infection:


  • Wipes MBR, replaces data in MBR with the text:


  • Inverts screen
  • Flips screen
  • Makes the screen appear to be melting
  • Makes the screen appear to be having glitches
  • Capable of forcing BSOD on victim's computer
  • Play random sounds

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .0
  • .1st
  • .3dm
  • .3mf
  • .600
  • .602
  • .7z
  • .7zip
  • .a
  • .aaf
  • .abw
  • .accdb
  • .acl
  • .aep
  • .aepx
  • .aet
  • .ahk
  • .ai
  • .aps
  • .as
  • .as3
  • .asc
  • .asp
  • .aspx
  • .assets
  • .asx
  • .avi
  • .bas
  • .bep
  • .bmp
  • .c
  • .cbf
  • .cbfx
  • .cer
  • .cfa
  • .class
  • .config
  • .contact
  • .cpp
  • .cs
  • .css
  • .csv
  • .dat
  • .db
  • .dbf
  • .deb
  • .dic
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dvi
  • .dwg
  • .dxf
  • .ebf
  • .ebfx
  • .ebuild
  • .efx
  • .eps
  • .ev3
  • .ev3
  • .exp
  • .fits
  • .fla
  • .flv
  • .fnt
  • .gif
  • .go
  • .gz
  • .h
  • .hmg
  • .htm
  • .html
  • .ico
  • .idml
  • .inc
  • .indb
  • .indd
  • .indl
  • .indt
  • .inx
  • .iso
  • .jar
  • .java
  • .jpeg
  • .jpg
  • .js
  • .json
  • .ldr
  • .lic
  • .loc
  • .lock
  • .log
  • .lua
  • .lxf
  • .m3u8
  • .m4a
  • .max
  • .mcfunction
  • .mcmeta
  • .md2
  • .md3
  • .md4
  • .md5
  • .mdb
  • .mkv
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .msg
  • .msi
  • .ncb
  • .nuc
  • .nut
  • .obj
  • .object
  • .odf
  • .odp
  • .odt
  • .ogg
  • .otf
  • .pdb
  • .pdf
  • .pek
  • .pez
  • .php
  • .php?
  • .piv
  • .pkf
  • .pl
  • .plb
  • .plg
  • .pm
  • .pmd
  • .png
  • .pot
  • .potm
  • .potx
  • .pov
  • .ppj
  • .pps
  • .ppt
  • .pptm
  • .pptx
  • .prefs
  • .prel
  • .prfpset
  • .prproj
  • .prsl
  • .ps
  • .ps
  • .ps.gz
  • .psc
  • .psd
  • .psm1
  • .py
  • .python
  • .rar
  • .raw
  • .rb
  • .rbt
  • .rc
  • .res
  • .resource
  • .resx
  • .rex
  • .rtf
  • .rxe
  • .sdf
  • .sdl
  • .ses
  • .silo
  • .sln
  • .sql
  • .sti
  • .svg
  • .swf
  • .swift
  • .tab
  • .tar.gz
  • .tdf
  • .tif
  • .tiff
  • .tpk
  • .txt
  • .udo
  • .umod
  • .vb
  • .vcf
  • .vob
  • .w3d
  • .war
  • .webp
  • .wmv
  • .wpd
  • .wps
  • .wtv
  • .wve
  • .x
  • .xla
  • .xlam
  • .xll
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xmp
  • .xpl
  • .xps
  • .xqx
  • .xsl-fo
  • .z
  • .zip
  • ilk

It encrypts files found in the following folders:

  • %Cookies%
  • %Desktop%
  • %AppDataLocal%
  • %Application Data%
  • %User Profile%\Music
  • %User Profile%\Videos
  • %User Profile%\Pictures

(Note: %Cookies% is the Internet Explorer browser cookies folder, which is usually C:\Documents and Settings\{user name}\Cookies on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Cookies on Windows Vista and 7, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCookies on Windows 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.. %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.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming 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.)

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

  • .ForgiveMe

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.682.03

FIRST VSAPI PATTERN DATE:

11 Dec 2018

VSAPI OPR PATTERN File:

14.683.00

VSAPI OPR PATTERN Date:

12 Dec 2018

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 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.MSIL.LIGMA.THIAOAH

[ 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

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  
  • C:\WinWOW32

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoDesktop = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • DisableTaskMgr = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • DisableCMD = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoControlPanel = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • HideClock = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoLogoff = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoWindowsUpdate = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoDrives = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\MobilityCenter
    • NoMobilityCenter = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoFolderOptions = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\System
    • DisableRegistryTools = 1

Step 6

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_CLASSES_ROOT\txtfile\DefaultIcon
    • From: (Default) = C:\WinWOW32\icon.ico
      To: (Default) = %System Root%\system32\imageres.dll, -102
  • In HKEY_CLASSES_ROOT\exefile\DefaultIcon
    • From: (Default) = C:\WinWOW32\icon.ico
      To: (Default) = %1
  • In HKEY_CLASSES_ROOT\VBSfile\DefaultIcon
    • From: (Default) = C:\WinWOW32\icon.ico
      To: (Default) = %System Root%\System32\WScript.exe, 2
  • In HKEY_CLASSES_ROOT\batfile\DefaultIcon
    • From: (Default) = C:\WinWOW32\icon.ico
      To: (Default) = %System Root%\System32\imageres.dll, -68
  • In HKEY_CLASSES_ROOT\dllfile\DefaultIcon
    • From: (Default) = C:\WinWOW32\icon.ico
      To: (Default) = imageres.dll, -67
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: AutoRestartShell = 0
      To: AutoRestartShell = 1
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: EnableLUA = 0
      To: EnableLUA = 1
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Defender
    • From: DisableAntiSpyware = 1
      To: DisableAntiSpyware = 0
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: ConsentPromptBehaviorAdmin = 0
      To: ConsentPromptBehaviorAdmin = 5
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = 2
      To: Hidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: ShowSuperHidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = 1
      To: HideFileExt = 0
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: legalnoticecaption = LIGMA
      To: legalnoticecaption = ""
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: legalnoticetext = Your Computer Got Fucked By LIGMA!
      To: legalnoticetext = ""

Step 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM.MSIL.LIGMA.THIAOAH. 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 8

Restore encrypted files from backup.


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