Analysis by: Bren Matthew Ebriega
ALIASES:

a variant of Win32/Filecoder.OCN trojan (NOD32); Malware-Cryptor.Inject.gen (VBA32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 133,632 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 12 Nov 2020

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 adds the following processes:

  • %System%\cipher.exe /w:{Drive Letter}:
  • %System%\wbadmin.exe delete catalog -quiet
  • %System%\bcdedit.exe /set {default} recoveryenabled no
  • %System%\bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures
  • %System%\schtasks.exe /Change /TN "\Microsoft\Windows\SystemRestore\SR" /disable
  • %System%\wevtutil.exe cl Application
  • %System%\wevtutil.exe cl System
  • %System%\wevtutil.exe cl Setup
  • %System%\wevtutil.exe cl Security
  • %System%\wevtutil.exe sl Security /e:false
  • %System%\fsutil.exe usn deletejournal /D {Drive Letter}:

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableConfig = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore
DisableConfig = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore
DisableSR = 1

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • {Original Filename}.{Original extension}.{Targeted Company Acronym}911-{Random Characters}

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

  • {Encrypted Directory}\!NEWS_FOR_{Targeted Company Acronym}!.txt

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.354.01
FIRST VSAPI PATTERN DATE: 16 Nov 2020
VSAPI OPR PATTERN File: 16.355.00
VSAPI OPR PATTERN Date: 17 Nov 2020

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     Troj.Win32.TRX.XXPE50FFF038

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

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 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.

 
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
  • DisableConfig = 1
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
  • DisableSR = 1
  • HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\SystemRestore
  • DisableConfig = 1
  • HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\SystemRestore
  • DisableSR = 1

Step 5

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.
  • {Encrypted Directory}\!NEWS_FOR_{Targeted Company Acronym}!.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.EXX.YAAK-B. 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 7

Restore encrypted files from backup.


Did this description help? Tell us how we did.