Analysis by: Arianne Grace Dela Cruz
ALIASES:

Trojan:MSIL/SmallDownloader!MTB (MICROSOFT); HEUR:Trojan-Banker.MSIL.Passteal.gen (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Coinminer

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

This Coinminer 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.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 8,192 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 10 Aug 2021
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Coinminer 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:

Download Routine

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

  • https://cdn.{BLOCKED}dapp.com/attachments/873244194234318850/873625288863535154/pctool.exe - contains the coinminer module

It saves the files it downloads using the following names:

  • %User Temp%\LzmwAqmV.exe

(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).)

As of this writing, the said sites are inaccessible.

Other Details

This Coinminer does the following:

  • It will not proceed with its intended routine if any of the following conditions are met:
    • Presence of the following strings in the machine's manufacturer model:
      • Virtual
      • vmware
      • VirtualBox
    • Running under a debugger or emulator

It checks if the following virtual machine or sandbox related module(s) is loaded in the affected system:

  • SbieDll.dll - terminates itself when found

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.898.03
FIRST VSAPI PATTERN DATE: 11 Aug 2021
VSAPI OPR PATTERN File: 16.899.00
VSAPI OPR PATTERN Date: 12 Aug 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:

     Troj.Win32.TRX.XXPE50FFF046

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.
  • %User Temp%\LzmwAqmV.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as Coinminer.MSIL.MALXMR.TIAOODBH. 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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