Analysis by: Raymart Christian Yambot
ALIASES:

Win32:Trojan-gen (AVAST)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

This Backdoor 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: 721,408 bytes
File Type: DLL
Memory Resident: No
Initial Samples Received Date: 14 Jul 2023
Payload: Drops files, Modifies system registry

Arrival Details

This Backdoor 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 Backdoor drops the following files:

  • %System Root%\DBEngin.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other System Modifications

This Backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Direct3D\MostRecentApplication
Name = rundll32.exe

HKEY_CURRENT_USER\Software\Microsoft\
Direct3D\MostRecentApplication
Name = Explorer.EXE

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.712.07
FIRST VSAPI PATTERN DATE: 11 May 2021
VSAPI OPR PATTERN File: 16.713.00
VSAPI OPR PATTERN Date: 12 May 2021

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:

     
    • PE.Win32.TRX.XXPE50FFF070

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 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.
  • %System Root%\DBEngin.exe

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Direct3D\MostRecentApplication
    • Name = rundll32.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Direct3D\MostRecentApplication
    • Name = Explorer.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.BLAME.SMZTHE-A. 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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