RANSOM_HIDDENTEARGEMBOK.A

April 14, 2017
 Analysis by: Ryan Paolo Maglaque
 ALIASES:

Ransom.HiddenTear(Norton);Mal/Cryptear-A(Sophos);Gen:Heur.Ransom.HiddenTears.1(Bitdefender)

 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.

  TECHNICAL DETAILS

File Size:

3,095,040 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 Apr 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:

  • C:\Users\{Profile Name}\Documents\PENTING !!!.htm ← Ransom Note
  • C:\Users\{Profile Name}\Desktop\test\READ_IT.txt ← Ransom Note

Other Details

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

  • http://{BLOCKED}.{BLOCKED}.71.54/ransomware/write.php?info={Computername}-{Username}%20{Key}

It encrypts files with the following extensions:

  • .pdf
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .jpg
  • .png

It renames encrypted files using the following names:

  • {Original File Name and Extension}.gembok

It does the following:

  • Drops the following ransom note:
  • Drops a text file with the following contents:
  • Encrypts files in C:\Users\{Profile Name}\Documents\Faizal

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.320.02

FIRST VSAPI PATTERN DATE:

05 Apr 2017

VSAPI OPR PATTERN File:

13.321.00

VSAPI OPR PATTERN Date:

06 Apr 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.  
  • C:\Users\{Profile Name}\Documents\PENTING !!!.htm
  • C:\Users\{Profile Name}\Desktop\test\READ_IT.txt

Step 4

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