Analysis by: Jeffrey Francis Bonaobra
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

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. It avoids encrypting files with the following file extensions.

  TECHNICAL DETAILS

File Size: 1,063,424 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 28 Mar 2022

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 Name
  • IP address
  • OS Version

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

  • {BLOCKED}.{BLOCKED}.75.81

Other Details

This Ransomware does the following:

  • It deletes files with the following file extensions:
    • bak
    • bco
    • vbk
    • vib
    • log
  • It encrypts the following drives:
    • Remote (Network) Drives
    • Fixed Drives
    • Removable Drives

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • {Original File Name}.{Original File Extension}.Lorenz.sz40

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

  • HELP.TXT

It avoids encrypting files found in the following folders:

  • Program Files
  • Common Files
  • AppData
  • WINDOWS
  • WindowsApps
  • Windows
  • $Recycle.Bin
  • Packages
  • Microsoft
  • Local
  • Program Data
  • All Users

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

  • {Encrypted Folder}\HELP.TXT
  • %Desktop%\HELP.TXT

It avoids encrypting files with the following file extensions:

  • dll
  • exe
  • sys
  • bin
  • lib
  • pif
  • sz40
  • mui
  • msi

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 17.542.04
FIRST VSAPI PATTERN DATE: 03 May 2022
VSAPI OPR PATTERN File: 17.543.00
VSAPI OPR PATTERN Date: 04 May 2022

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.Win32.TRX.XXPE50FFF054

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 4

Search and delete these files

[ 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.  
  • {Encrypted Folder}\HELP.TXT
  • %Desktop%\HELP.TXT

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.THUNDERCRYPT.D. 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 6

Restore encrypted files from backup.


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