Analysis by: Carlos Villegas Madrid
ALIASES:

Trojan-Ransom.FileCrypter (IKARUS)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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 terminates itself if it detects it is being run in a virtual environment.

  TECHNICAL DETAILS

File Size: 108,544 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 06 Feb 2023
Payload: Encrypts files, Displays message/message boxes, Terminates itself in a virtual environment

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 leaves text files that serve as ransom notes containing the following:

  • {Encrypted Directory}\ReadMe.txt

Other Details

This Ransomware terminates itself if it detects it is being run in a virtual environment.

It does the following:

  • It encrypts files found in the following drive types:
    • Fixed drive
    • Network drive
  • It uses WQL to delete shadow copies.

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

  • Windows
  • ProgramData
  • $Recycle.bin
  • System Volume Information

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

  • .TZW

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.408.04
FIRST VSAPI PATTERN DATE: 26 Apr 2023
VSAPI OPR PATTERN File: 18.409.00
VSAPI OPR PATTERN Date: 27 Apr 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.Win32.TRX.XXPE50FFF065

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 Directory}\ReadMe.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as Ransom.Win32.CRYPTOLOCK.E. 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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