Analysis by: Raymart Christian Yambot

ALIASES:

UDS:Trojan-Ransom.Linux.Babuk.inc (KASPERSKY)

 PLATFORM:

Linux

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size: 68,000 bytes
Memory Resident: No
Initial Samples Received Date: 15 Dec 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.

Installation

This Ransomware drops and executes the following files:

  • If the '-esxi' parameter is used:
    • {Malware File Path}/kill

Other Details

This Ransomware accepts the following parameters:

  • --debug → Print debugging logs of the malware to the terminal.
  • --daemon → Creates a duplicate child process of itself.
  • --file {File Path} → Encrypts the specified file.
  • --dir {Direcrtory Path} → Encrypts the specified directory.
    • --motd → Modifies the content of the "Message of the Day" system file '/etc/motd' into the ransom note text.
  • --esxi → Kill ESXi servers. Disables autostart for the host, powers off all virtual machines, and remove all snapshots from each virtual machine.
    • --skip {Virtual Machine name} → Excludes the specified virtual machine from the termination process.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .vmdk
  • .vmem
  • .vmx
  • .vswp
  • .vmsn

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

  • INC

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

  • {original filename}.{original extension}.INC

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

  • {Encypted Directory}\INC-README.txt
  • {Encypted Directory}\INC-README.html

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.880.04
FIRST VSAPI PATTERN DATE: 15 Dec 2023
VSAPI OPR PATTERN File: 18.881.00
VSAPI OPR PATTERN Date: 16 Dec 2023

Step 1

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.  
  • {Encypted Directory}\INC-README.txt
  • {Encypted Directory}\INC-README.html
  • {Malware File Path}/kill

Step 2

Scan your computer with your Trend Micro product to delete files detected as Ransom.Linux.RANINC.YXDLOT. 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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