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Ransom.Linux.TRIGONA.THCBBBC

June 20, 2023
 Analysis by: Ricardo III Valdez
 ALIASES:

UDS:Trojan-Ransom.Linux.Agent.a (KASPERSKY)

 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 drops files as ransom note.

  TECHNICAL DETAILS

File Size:

1,808,326 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

22 Mar 2023

Payload:

Collects system information, 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.

Information Theft

This Ransomware gathers the following data:

  • Computer ID
  • Computer Name
  • Host Name
  • Boot time
  • Machine ID
  • Processor Architecture
  • OS version
  • Local Disk Information
  • Keyboard Lists
  • Main Language
  • System User
  • Workgroup

Other Details

This Ransomware does the following:

  • It displays the following on the terminal after encrypting files:

It accepts the following parameters:

  • /full ← Encrypts full content of files
  • /test_cid ← Specifies the Computer ID to use
  • /test_vid ← Specifies the Victim ID to use
  • /p or /path ← Specifies the path to recursively encrypt
  • /erase ← Overwrite files with NULL bytes, appends "._erased" extension and deletes it.
  • /is_testing ← Sets the testing flag (Must be used with /test_cid and /test_vid)
  • /shdwn ← Shuts down the system

Ransomware Routine

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

  • /proc/
  • /sys/
  • /run/
  • /dev/
  • /lib/
  • /lib64/
  • /bin/
  • /sbin/
  • /boot/
  • /etc/
  • /share/
  • systemd
  • kernel

It renames encrypted files using the following names:

  • {Random Characters}._locked

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

  • \tmp\how_to_decrypt.txt
  • {Encrypted Directory}\how_to_decrypt.txt

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.448.09

FIRST VSAPI PATTERN DATE:

17 May 2023

VSAPI OPR PATTERN File:

18.449.00

VSAPI OPR PATTERN Date:

18 May 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.XXELFC1DFF029

Step 2

Scan your computer with your Trend Micro product to delete files detected as Ransom.Linux.TRIGONA.THCBBBC. 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:


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