RANSOM_WNDIE.B

 Analysis by: Rheniel Rhay Ramos

 ALIASES:

Trojan.MSIL.DOTHETUK.nfz (Kaspersky); Ransom.WannaDie (Malwarebytes); Ransom:Win32/Genasom (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 adds certain registry entries to disable the Task Manager. This action prevents users from terminating the malware process, which can usually be done via the Task Manager.

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

  TECHNICAL DETAILS

File Size:

824,832 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

17 Nov 2017

Payload:

Drops files, 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.

Installation

This Ransomware drops the following files:

  • {Executed Malware Location}\proc.bat -> used to grant the user access rights
  • {Executed Malware Location}\pros.vbs -> used to run proc.bat
  • {Executed Malware Location}\@WannaDecrypt0r.png -> used as wallpaper
  • {Executed Malware Location}\a.wndi
  • {Executed Malware Location}\t.wndi
  • {Executed Malware Location}\d.wndi

It drops and executes the following files:

  • {Executed Malware Location}\@WannaDecrypt0r.exe

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

  • wanadie

Autostart Technique

This Ransomware drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\ms.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Ransomware adds the following registry entries to disable the Task Manager:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"

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

Other Details

This Ransomware displays a pop-up window with the following message:


It does the following:

  • It sets the attribute of its initial copy to hidden

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .dt
  • .1cd
  • .DT
  • .md
  • .dt
  • .hbk
  • .xltm
  • .xltx
  • .xlc
  • .xlm
  • .xlt
  • .hbk
  • .xlw
  • .xlsb
  • .xlsm
  • .xlsx
  • .xls
  • .html
  • htm
  • .csv
  • .dat
  • .ged
  • .key
  • .keychain
  • .pps
  • .ppt
  • .pptx
  • .sdf
  • .tar
  • .tax2014
  • .tax2015
  • .vcf
  • .xml

It encrypts files found in the following folders:

  • %User Profile%\Recent
  • %User Profile%\MyPictures
  • %User Profile%\MyMusic
  • %User Profile%\MyVideos
  • %User Profile%\Personal
  • %User Profile%\Favorites
  • %All Users Profile%\Documents
  • %All Users Profile%\Pictures
  • %All Users Profile%\Music
  • %All Users Profile%\Videos
  • %All Users Profile%\Desktop
  • %Desktop%

(Note: %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 and 7.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • .wndie

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.798.04

FIRST VSAPI PATTERN DATE:

17 Nov 2017

VSAPI OPR PATTERN File:

13.799.00

VSAPI OPR PATTERN Date:

18 Nov 2017

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

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\System
    • DisableTaskMgr = "1"

Step 4

Identify and terminate files detected as RANSOM_WNDIE.B

[ 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 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 Startup%\ms.lnk
  • {Executed Malware Location}\proc.bat -> used to grant the user access rights
  • {Executed Malware Location}\pros.vbs -> used to run <i>proc.bat</i>
  • {Executed Malware Location}\@WannaDecrypt0r.png -> used as wallpaper
  • {Executed Malware Location}\@WannaDecrypt0r.exe
  • {Executed Malware Location}\a.wndi
  • {Executed Malware Location}\t.wndi
  • {Executed Malware Location}\d.wndi

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_WNDIE.B. 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.

Step 8

Reset your Desktop properties

[ Learn More ]


Did this description help? Tell us how we did.