Analysis by: Rheniel Rhay Ramos

ALIASES:

Ransom.BTCWare (Malwarebytes); Ransomware-FTD!8BCFFC24D7A5 (McAfee); Ransom:MSIL/Ryzerlo.A (Microsoft)

 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.

  TECHNICAL DETAILS

File Size: 47,104 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 20 Oct 2017
Payload: Connects to URLs/IPs, Encrypts files, Deletes 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 terminates itself if it finds the following processes in the affected system's memory:

  • wireshark
  • dnspy
  • ilspy
  • fiddler
  • fiddler4

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Main = "{Malware Location}\{Executed Malware}"

Other System Modifications

This Ransomware sets the system's desktop wallpaper to the following image:

Download Routine

This Ransomware connects to the following URL(s) to download its component file(s):

  • https://i.{BLOCKED}r.com/{BLOCKED}h.jpg

It saves the files it downloads using the following names:

  • C:\{User Name}\walpaper.jpg -> used as wallpaper

Other Details

This Ransomware connects to the following URL(s) to check for an Internet connection:

  • https://www.google.com

It does the following:

  • It contains several codes for the following functions which will not be executed:
    • Encrypt files in specific folders
    • Encrypt files with specific extension
    • Append an extension to encrypted files
    • Drop ransom note
    • Delete files in all drives
    • Connect to a website to check IP address
    • Gather information of affected computer
    • Send information gathered to a specific URL

It locks the screen and displays the following image:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.736.04
FIRST VSAPI PATTERN DATE: 23 Oct 2017
VSAPI OPR PATTERN File: 13.737.00
VSAPI OPR PATTERN Date: 24 Oct 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_HIDDENTEARORDINAL.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

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
    • Main = "{Malware Location}\{Executed Malware}"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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:\{User Name}\walpaper.jpg

Step 6

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