Analysis by: Wilbert Vidal
ALIASES:

Trojan.Ransom.Onion3Cry (ALYac); Ransom:Win32/HiddenTear.gen (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: 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 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 is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 404,307 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 26 Sep 2017
Payload: Encrypts files, Drops 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:

  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\### DECRYPT MY FILES ###.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###1.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###11.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###2.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###4.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\dez.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\goupdate.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\winupdate.exe.lnk

(Note: %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.)

It drops and executes the following files:

  • %System Root%\Users\Public\dez.exe - detected as TROJ_GEN.R00EC0PJ217
  • %Application Data%\Local\Gogle\update\winupdate.exe - Fake update form - detected as Suspicious_GEN.F47V0926
  • %Application Data%\Local\Gogle\update\goupdate.exe - also detected as Ransom_HIDDENTERONION.A

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

It creates the following folders:

  • %Application Data%\Local\Gogle\update
  • %Application Data%\Local\Gogle
  • %Application Data%\Local

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

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

Other Details

This Ransomware does the following:

  • This ransomware displaying fake update window application:

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .index
  • .zip
  • .rar
  • .css
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .bmp
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php
  • .asp
  • .aspx
  • .xml
  • .psd
  • .bk
  • .bat
  • .mp3
  • .mp4
  • .wav
  • .wma
  • .avi
  • .divx
  • .mkv
  • .mpeg
  • .wmv
  • .mov
  • .ogg
  • .tmp
  • .xlxx
  • .docxx
  • .msi
  • .dbx
  • .txt
  • .pst
  • .doc
  • .docx
  • .xls
  • .jpg
  • .pst
  • .pdf
  • .MP4
  • .gbk
  • .ico
  • .xls
  • .dat
  • .JPG
  • .mdw
  • .REC
  • .DEC
  • .cns
  • .RE

It encrypts files found in the following folders:

  • c:\

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

  • .onion3cry-open-DECRYPTMYFILES

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

  • %System Root%\Users\Public\Desktop\### DECRYPT MY FILES ###.exe
  • %System Root%\Users\Public\Documents\### DECRYPT MY FILES ###1.exe
  • %Application Data%\### DECRYPT MY FILES ###11.exe
  • %System Root%\Users\Public\### DECRYPT MY FILES ###2.exe
  • %System Root%\### DECRYPT MY FILES ###4.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

NOTES:

This ransomware displays the following windowed application as its ransom note:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.682.04
FIRST VSAPI PATTERN DATE: 26 Sep 2017
VSAPI OPR PATTERN File: 13.683.00
VSAPI OPR PATTERN Date: 27 Sep 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

Search and delete these folders

[ 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.
  • %Application Data%\Local\Gogle\update
  • %Application Data%\Local\Gogle
  • %Application Data%\Local

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.
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\### DECRYPT MY FILES ###.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###1.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###11.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###2.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\### DECRYPT MY FILES ###4.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\dez.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\Startup\goupdate.exe.lnk
  • %All Users Profile%\Microsoft\Windows\Start Menu\Programs\winupdate.exe.lnk
  • %System Root%\Users\Public\dez.exe
  • %Application Data%\Local\Gogle\update\winupdate.exe
  • %Application Data%\Local\Gogle\update\goupdate.exe
  • %System Root%\Users\Public\Desktop\### DECRYPT MY FILES ###.exe
  • %System Root%\Users\Public\Documents\### DECRYPT MY FILES ###1.exe
  • %Application Data%\### DECRYPT MY FILES ###11.exe
  • %System Root%\Users\Public\### DECRYPT MY FILES ###2.exe
  • %System Root%\### DECRYPT MY FILES ###4.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_HIDDENTEARONION.A. 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 7

Restore encrypted files from backup.


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