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Ransom.Linux.NOESCAPE.THFOEBC

September 07, 2023
 Analysis by: Ricardo III Valdez
 ALIASES:

Trojan-Ransom.Noescape (IKARUS)

 PLATFORM:

Linux

 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 found in specific folders. It drops files as ransom note. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size:

5,301,056 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

05 Jun 2023

Payload:

Drops files, 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 the following files:

  • /{Shell Script File Path}/motd ← Ransom note in motd format
  • /{Shell Script File Path}/index.html ← Ransom note in html format

Information Theft

This Ransomware accepts the following parameters:

  • /{Specific path to encrypt}/

Other Details

This Ransomware does the following:

  • It requires the following file to proceed to its routines:
    • script_linux.sh <- Detected as Trojan.SH.NOESCAPE.THFOEBC
  • It empties the trash/recycle bin by deleting the following folder recursively:
    • /.local/share/Trash/info/
    • /.local/share/Trash/files/
  • It performs cleanup after execution by deleting the following files:
    • Log files
    • Backup files
    • /{Malware File Path}/{Malware Filename}.elf
    • /{Malware File Path}/index.html
    • /{Malware File Path}/motd
  • It replaces the /etc/motd with the ransom note
  • It uses the following configuration setup:
    • Local Configuration Key:
      • Local ID: 164f8295-{Random Characters}
      • IV Key: {Random Characters}
      • MP Key: {Random Characters}
    • Extensions:
      • Ignore: [elf, exe, lib, bin, sys]
      • Full: [sql]
    • Settings:
      • Build type: Linux
      • Add to autorun: False
      • Interval: 0
      • Print note: False
      • Set wallpaper: False
      • Large file size: 1024 mb
      • Spot size: 10 mb

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • Home directory ← Default

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

  • .BJDGAIHFHB

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

  • {Encrypted Directory}\HOW_TO_RECOVER_FILES.txt

It avoids encrypting files with the following file extensions:

  • .bin
  • .elf
  • .exe
  • .lib
  • .sys

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.492.02

FIRST VSAPI PATTERN DATE:

06 Jun 2023

VSAPI OPR PATTERN File:

18.493.00

VSAPI OPR PATTERN Date:

07 Jun 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.XXELFC1DFF030

Step 2

Scan your computer with your Trend Micro product to delete files detected as Ransom.Linux.NOESCAPE.THFOEBC. 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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