Analysis by: Marcus Ma. Antonio Capistrano
ALIASES:

Mal/Genasom-A (SOPHOS_LITE), Trojan:Win32/Tiggre!rfn (MICROSOFT), 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: Dropped by other malware, 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.

  TECHNICAL DETAILS

File Size: 83,456 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 10 Dec 2017
Payload: Connects to URLs/IPs, Displays message/message boxes, 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.

Installation

This Ransomware drops the following files:

  • {Malware file path}\master_public_key.info
  • {Malware file path}\master_pri_key.info

Other Details

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

  • http://0cf5ff34.{BLOCKED}k.io/config/check/{user define token}/validate/{user defined key}
  • http://0cf5ff34.{BLOCKED}k.io/config/check/{user defined characters}

It does the following:

  • When executed, the malware informs the user of the encryption through a window message:
  • After the malware has finished its encryption routine it displays the following:

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .JPG
  • .GIF
  • .PDF
  • .PNG
  • .NEF
  • .ZIP
  • .RAR
  • .TAR
  • .GZ
  • .CS
  • .VB
  • .JAVA
  • .CLASS
  • .JS
  • .VBS
  • .CSC
  • .JSON
  • .TXT
  • .C
  • .CPP
  • .H
  • .CONFIG
  • .PY
  • .R
  • .XAML
  • .JSP
  • .PHP
  • .DOC
  • .DOCX
  • .XLS
  • .XLSX
  • .PPT
  • .PPTX
  • .MP3
  • .MP4
  • .AVI
  • .MPEG
  • .PST
  • .MSG
  • .EML
  • .DBX
  • .MBX
  • .WAB
  • .CAB

It encrypts files found in the following folders:

  • F:\TEMP\{subfolders if any}
  • D:\TEMP\ {subfolders if any}
  • F:\Hardware-Ransom\ {subfolders if any}

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.838.03
FIRST VSAPI PATTERN DATE: 12 Dec 2017
VSAPI OPR PATTERN File: 13.839.00
VSAPI OPR PATTERN Date: 13 Dec 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

Identify and terminate files detected as RANSOM_MAKEUCRY.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

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 file path}\master_public_key.info
  • {Malware file path}\master_pri_key.info

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_MAKEUCRY.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 6

Restore encrypted files from backup.


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