Analysis by: Ryan Paolo Maglaque

ALIASES:

Ransom.HiddenTear!g1(Norton);Mal/Cryptear-A(Sophos)

 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 connects to certain websites to send and receive information. It deletes itself after execution.

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

  TECHNICAL DETAILS

File Size: 16,384 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 15 May 2017
Payload: Encrypts files, Connects to URLs/IPs, 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:

  • {Malware Directory}\de.bat ← used to delete self
  • %Application Data%\del1.bat ← used to execute commands

(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 Details

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

  • https://{BLOCKED}are.{BLOCKED}ons/1/target.php?id={guid}&key={key}

It does the following:

  • Renames files with following extensions to {Original File Name and Extension}.locked and try to set their attribute to hidden(doesn't encrypt):
    • .zip
    • .ldf
    • .ndf
    • .err
    • .myd
    • .mpg
    • .vhd
    • .iso
    • .pst
    • .bkf
    • .bak
  • Run %Application Data%\del1.bat to try and execute the following commands:
    • vssadmin delete shadows /all /quiet
    • bcedit.exe /set {default} recovery enabled no
    • bcedit.exe /set {default} bootstatuspolicy ignoreallfailures

(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.)

It deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .MYOX
  • .GPS
  • .gps
  • .PNG
  • .png
  • .MDF
  • .ldf
  • .mdf
  • .trn
  • .pdf
  • .myi
  • .prn
  • .data
  • .ctf
  • .mkd
  • .ziz
  • .pxf
  • .dst
  • .eps
  • .tlf
  • .ltf
  • .cdr
  • .pmd
  • .ai
  • .txt
  • .qbw
  • .QBB
  • .qbb
  • .QBW
  • .TLG
  • .JPG
  • .tlg
  • .ecw
  • .pdf
  • .DBF
  • .PDF
  • .frm
  • .pix
  • .accdb
  • .mdb
  • .cdr
  • .eps
  • .tif
  • .msg
  • .asmx
  • .rpt
  • .arw
  • .qbo
  • .qbw
  • .sldprt
  • .dwf
  • .doc
  • .adi
  • .adt
  • .docx
  • .altr
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .png
  • .csv
  • .sql
  • sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .bat
  • .js
  • .css
  • .sqlite
  • .dwg
  • .jpeg

It avoids encrypting files with the following strings in their file path:

  • Program Files
  • Windows
  • Program Data

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

  • .locked

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

  • {Encrypted file directory}\Restore_your_files.txt

It leaves text files that serve as ransom notes containing the following text:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.408.08
FIRST VSAPI PATTERN DATE: 15 May 2017
VSAPI OPR PATTERN File: 13.409.00
VSAPI OPR PATTERN Date: 16 May 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

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.  
  • {Malware Directory}\de.bat
  • %Application Data%\del1.bat
  • {Encrypted file directory}\Restore_your_files.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_HIDDENTEARMAY.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 5

Restore encrypted files from backup.


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