Analysis by: Rheniel Rhay Ramos
ALIASES:

Ransom.HiddenTear.Generic (Malwarebytes); Ransom:MSIL/Ryzerlo.A (Microsoft); Ransom.HiddenTear!g1 (Symantec)

 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

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

  TECHNICAL DETAILS

File Size: 347,136 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 04 Sep 2017
Payload: Connects to URLs/IPs, Leaves ransom note, 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.

Other Details

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

  • https://keyunlock.{BLOCKED}hostapp.com/Victim/ransom.php?

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .txt
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .odt
  • .jpg
  • .png
  • .csv
  • .sql
  • .mdb
  • .sln
  • .php
  • .asp
  • .aspx
  • .html
  • .xml
  • .psd
  • .mdb
  • .bmp
  • .gif
  • .mp3
  • .mpg
  • .mpeg
  • .pdf
  • .zip
  • .rar

It encrypts files found in the following folders:

  • %User Profile%C:/

(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.)

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

  • .locked

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

  • %Desktop%\test\READ_IT.txt

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

  • Oooopppsss Your Files Has Been Encrypted
    Your Unique GUID for Decrypt: j43as8fk-29gp-61da-3671-h03c83472r74
    SEND ME SOME 0.022 Bitcoin on Adress: {BLOCKED}bLT1VSMUqXaSqsYUAwcGU4evkbJo :
    After Confirming The Payment, ALL YOUR FILES CAN BE DECRYPTED.
    If you do not make payment within 48 Hrs, you will lose the ability to decrypt them.
    Make your Bitcoin Wallet on: https://www.coinbase.com/ or http://blockchain.info
    How to buy /sell and send Bitcoin :
    1)https://support.coinbase.com/customer/en/portal/topics/796531-payment-method-verification/articles
    2)https://support.coinbase.com/customer/en/portal/topics/601090-buying-selling-bitcoin/articles
    3)https://support.coinbase.com/customer/en/portal/topics/601112-sending-receiving-bitcoin/articles
    After the payment, enter the wallet from which paid, and email, in which contact you. {BLOCKED}123@{BLOCKED}mail.com
    After receiving the payment, we will contact you.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.638.08
FIRST VSAPI PATTERN DATE: 04 Sep 2017
VSAPI OPR PATTERN File: 13.639.00
VSAPI OPR PATTERN Date: 05 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

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.  
  • %Desktop%\test\READ_IT.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_HIDDENTEARULTIMO.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:

Step 5

Restore encrypted files from backup.


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