Trojan.Win32.MALXMR.THHADBO

August 17, 2020
 Analysis by: Karen Ivy Titiwa
 ALIASES:

Trojan.GenericKD.43646047(BITDEFENDER); TR/AD.PSLoader.kdimb(ANTIVIR)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet

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:

14898565 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Aug 2020

Payload:

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:

It adds the following processes:

  • %User Temp%\setup.exe
  • %System%\WScript.exe %User Temp%\mstsc.vbs

(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).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR SFX
{%System Root%}%%Users%{User Name}%AppData%Local%Temp = "%User Temp%"

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

16.164.05

FIRST VSAPI PATTERN DATE:

14 Aug 2020

VSAPI OPR PATTERN File:

16.165.00

VSAPI OPR PATTERN Date:

15 Aug 2020

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

Identify and terminate files detected as Trojan.Win32.MALXMR.THHADBO

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Restore this modified 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\WinRAR SFX
    • {%System Root%}%%Users%{User Name}%AppData%Local%Temp = %User Temp%

Step 5

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.
  • %User Temp%\setup.exe
  • %User Temp%\mstsc.vbs

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.MALXMR.THHADBO. 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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