Analysis by: Jayvee Mark Villaroman
ALIASES:

Ransom:Win32/CylanCrypt.PAC!MTB (MICROSOFT), Trojan-Ransom.FileCrypter (IKARUS)

 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.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 141,824 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 17 Sep 2023
Payload: Drops files, 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:

  • {Malware Directory}\RUN.dll

It adds the following processes:

  • cmd.exe /c vssadmin.exe delete shadows /all /quiet

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\elibeMutex

Other Details

This Ransomware does the following:

  • Sets the current process priority to highest
  • Empties the recycle bin
  • Uses the system's max thread count upon execution
  • Encrypts removable, fixed, remote drives

It accepts the following parameters:

  • -path : Specify the path to encrypt
  • -ratio : Encryption ratio
  • -nomutex : Don't use mutex
  • -nonetdrive : Ignore encryption in network drives
  • -selfdel : Self-delete after execution

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • ntldr
  • ntuser.dat
  • bootsect.bak
  • ntuser.dat.log
  • autorun.inf
  • thumbs.db
  • iconcache.db
  • bootfont.bin
  • boot.ini
  • desktop.ini
  • ntuser.ini
  • bootmgr

It avoids encrypting files found in the following folders:

  • Windows
  • $Windows.~bt
  • $windows.~ws
  • windows.old
  • windows nt
  • Public
  • Intel
  • PerfLogs
  • System Volume Information
  • MSOCache
  • Default
  • Config.Msi

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

  • {Original File Name}.{Original Extension}.EMAIL=recoveryfile7@gmail.com.ID={Generated ID}.elibe

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

  • {Encrpyted Directory}\FILE ENCRYPTED.txt

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.704.02
FIRST VSAPI PATTERN DATE: 18 Sep 2023
VSAPI OPR PATTERN File: 18.705.00
VSAPI OPR PATTERN Date: 19 Sep 2023

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.XXPE50FFF072  

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

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 Directory}\RUN.dll
  • {Encrypted Directory}\FILE ENCRYPTED.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.BTCAZADI.THIAHBC. 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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