Ransom.Linux.BESTWOFOUR.A

November 30, 2023
 Analysis by: John Rainier Navato
 ALIASES:

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 encrypts files with specific file extensions. It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

16,888 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

29 Nov 2023

Payload:

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.

Other Details

This Ransomware does the following:

  • It dsplays log activity through console.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .csv
  • .docx
  • .json
  • .pdf
  • .sql
  • .txt
  • .xlsx
  • .xml

It encrypts files found in the following folders:

  • /forela-criticaldata/

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

  • .24bes

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

  • {Encrypted File Path}\{Encrypted File Name}.24bes_note.txt

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.848.05

FIRST VSAPI PATTERN DATE:

29 Nov 2023

VSAPI OPR PATTERN File:

18.845.00

VSAPI OPR PATTERN Date:

30 Nov 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.ELF.TRX.XXELFC1DFF034

Step 2

Scan your computer with your Trend Micro product to delete files detected as Ransom.Linux.BESTWOFOUR.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 3

Restore encrypted files from backup.


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