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Ransom.Linux.KUIPER.THAAHBD

February 06, 2024
 Analysis by: Melvin Jhun Palbusa
 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 drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

2,215,936 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

18 Jan 2024

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 prints the number of processors and execution logs to the console.
  • It checks if the file size is greater than 4,493,148,150 bytes. Only a certain percentage of the file will be encrypted.
  • It checks if the file extension is any of the following. These files will be encrypted in its entirety regardless of the file size.
    • .sql
    • .txt
    • .db
    • .json

It accepts the following parameters:

  • -help → Displays the help menu.
  • -kill {yes|no} → Kill loop for taskmgr, cmd, regedit, powershell. (Default: no)
  • -note {yes|no} → Paste note after directory change and encryption. (Default: yes)
  • -p {path} → Target folder to encrypt files
  • -reboot {yes|no} → Reboot after end encryption of all files or disks. (Default: yes)
  • -rename {yes|no} → Rename file after encryption. (Default: yes)
  • -bm {yes|no} → Encrypt big files first (Default: yes)

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • /bin
  • /boot
  • /dev
  • /etc
  • /initrd
  • /lib
  • /lib64
  • /libx32
  • /opt
  • /proc
  • /root
  • /run
  • /sbin
  • /srv
  • /sys
  • /tmp
  • /usr/
  • /var

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

  • .kuiper

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

  • {Encrypted directory}\README_TO_DECRYPT.txt

It avoids encrypting files with the following file extensions:

  • .bak
  • .bat
  • .bin
  • .blf
  • .cfg
  • .cmd
  • .com
  • .dat
  • .dll
  • .elf
  • .exe
  • .ini
  • .lnk
  • .msi
  • .rtf
  • .sys
  • .tmp

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.104.02

FIRST VSAPI PATTERN DATE:

18 Jan 2024

VSAPI OPR PATTERN File:

19.105.00

VSAPI OPR PATTERN Date:

19 Jan 2024

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.XXELFC1DFF036

Step 2

Scan your computer with your Trend Micro product to delete files detected as Ransom.Linux.KUIPER.THAAHBD. 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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