RANSOM_HIDDENTEARRADION.A

February 08, 2018
 Analysis by: Michael Jhon Ofiaza
 ALIASES:

Trojan.Win32.Bcex.awzl (Kaspersky) , Backdoor.Ratenjay (Norton) , Troj/Ramsil-C (Sophos Lite)

 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:

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 steals certain information from the system and/or the user.

It connects to certain websites to send and receive information.

It encrypts files with specific file extensions.

  TECHNICAL DETAILS

File Size:

246,784 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

12 Sep 2017

Payload:

Connects to URLs/IPs, Encrypts files, Displays message/message boxes

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:

  • %Desktop%\README_TO_DECRYPT_FILES.html - ransom note
  • %Desktop%\README_TO_DECRYPT_FILES.txt - ransom note
  • %Desktop%LESEN_SIE_MICH_UM_DATEIEN_ZU_ENTSCHLUSSELN.txt - ransom note
  • %Desktop%LISEZ-MOI_POUR_DECHIFFRER_LES_FICHIERS.txt - ransom note
  • %Desktop%LEAME_PARA_DESCIFRAR_ARCHIVOS.txt - ransom note
  • %Desktop%LEGGIMI_PER_DECIFRARE_I_FILES.txt - ransom note
  • %Desktop%LEESMIJ-BESTAND_VOOR_HET_DECODEREN_VAN_BESTANDEN.txt - ransom note
  • %Desktop%PROCHTI_MENYA_DLYA_RASSHIFROVKI_FAYLOV.txt - ransom note

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

  • Global\{malware name}

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Message_2017 = %Desktop%\README_TO_DECRYPT_FILES.html

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

Information Theft

This Ransomware steals the following information:

  • OS version
  • Username
  • Date of encryption
  • Machine name
  • IP address

Other Details

This Ransomware connects to the following website to send and receive information:

  • http://{BLOCKED}t5cud3p.onion.to/dash/{BLOCKED}f0bc73786d40fb3ad660f0b9.php
  • http://{BLOCKED}t5cud3p.onion.link/dash/{BLOCKED}f0bc73786d40fb3ad660f0b9.php

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .txt
  • .rtf
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .ods
  • .pdf
  • .jpg
  • .jpeg
  • .png
  • .gif
  • .bmp
  • .csv
  • .sql
  • .mdb
  • .db
  • .accdb
  • .sln
  • .php
  • .jsp
  • .asp
  • .aspx
  • .html
  • .htm
  • .xml
  • .psd
  • .cs
  • .java
  • .cpp
  • .cc
  • .cxx
  • .zip
  • .rar
  • .pst
  • .ost
  • .eml
  • .pab
  • .oab
  • .msg

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

  • .ransom

NOTES:

The ransom note contains the following text:

It displays the following image after execution:

The malware checks if the system date is before September 7, 2017 before encrypting files.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.654.03

FIRST VSAPI PATTERN DATE:

12 Sep 2017

VSAPI OPR PATTERN File:

13.655.00

VSAPI OPR PATTERN Date:

13 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

Restart in Safe Mode

[ Learn More ]

Step 4

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • From: "DisableTaskMgr" = 1
      To: "DisableTaskMgr" = 0

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\Run
    • Message_2017 = %Desktop%\\README_TO_DECRYPT_FILES.html

Step 6

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.
  • %Desktop%\\README_TO_DECRYPT_FILES.html
  • %Desktop%PROCHTI_MENYA_DLYA_RASSHIFROVKI_FAYLOV.txt
  • %Desktop%LESEN_SIE_MICH_UM_DATEIEN_ZU_ENTSCHLUSSELN.txt
  • %Desktop%LISEZ-MOI_POUR_DECHIFFRER_LES_FICHIERS.txt
  • %Desktop%LEAME_PARA_DESCIFRAR_ARCHIVOS.txt
  • %Desktop%LEGGIMI_PER_DECIFRARE_I_FILES.txt
  • %Desktop%LEESMIJ-BESTAND_VOOR_HET_DECODEREN_VAN_BESTANDEN.txt

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_HIDDENTEARRADION.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 8

Restore encrypted files from backup.

Step 9

Scan your computer with your Trend Micro product to delete files detected as RANSOM_HIDDENTEARRADION.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 the following Trend Micro Support pages for more information:


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