Analysis by: Paolo Ronniel Labrador

ALIASES:

Trojan:PowerShell/Asyncrat.AO!MTB (MICROSOFT)

 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.

It logs a user's keystrokes to steal information.

  TECHNICAL DETAILS

File Size: 1,637,732 bytes
File Type: PS1
Memory Resident: Yes
Initial Samples Received Date: 27 Jun 2025
Payload: Collects system information, Connects to URLs/IPs, Steals information, Drops files

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:

  • %User Temp%\Log.tmp → contains key logs

(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).)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • AsccMutexxxxxssmm1_{random}

Backdoor Routine

This Backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.{BLOCKED}.15
  • {BLOCKED}aupload.co
  • {BLOCKED}upload.co
  • {BLOCKED}.{BLOCKED}.{BLOCKED}.19
  • {BLOCKED}c.serveftp.net
  • {BLOCKED}ic236922.serveftp.net

It connects to the following uncommon ports:

  • 3322

Information Theft

This Backdoor gathers the following data:

  • HWID = Hardware Identifiers
  • User = Username
  • OS = OS Information
  • Path = Path of the malware
  • Admin = If the malware is running with Admin Access
  • Performance = Current Active Window
  • Antivirus = Antivirus applications in the system
  • If the following cryptocurrency wallet and 2FA browser extensions exist in the affected system:
    • Firefox
      • MetaMask
    • Google Chrome
      • Authenticator
      • Binance (BEW Lite)
      • BitKeep (BitGet Wallet)
      • BitPay
      • Coinbase
      • Exodus (TronLink)
      • MetaMask
      • Phantom
      • Ronin
      • Trust
    • Brave
      • Authenticator
      • MetaMask
      • Phantom
    • Edge
      • Authenticator
      • Binance
      • MetaMask
  • If the following cryptocurrency applications exist in the affected system:
    • Atomic
    • Binance
    • Bitcoin
    • Coinomi
    • Electrum
    • ErgoWallet
    • Exodus
    • Ledger Live
  • LastTime = Last activity time of the affected system

It logs a user's keystrokes to steal information.

Other Details

This Backdoor does the following:

  • It decrypts and executes an MSIL DLL loader directly in memory.
  • It checks for the existence of the following files but displays a fake error regardless of whether they exist:
    • %Program Files%\AVG\Antivirus\AVGUI.exe
    • %Program Files%\Avast Software\Avast\AvastUI.exe
  • It executes the following file and injects malicious code from an embedded MSIL EXE payload into the newly created process:
    • %Windows%\Microsoft.NET\Framework\{version}\{random exe file}

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 20.312.04
FIRST VSAPI PATTERN DATE: 08 Jul 2025
VSAPI OPR PATTERN File: 20.313.00
VSAPI OPR PATTERN Date: 09 Jul 2025

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

Restart in Safe Mode

[ Learn More ]

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%\Log.tmp

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.PS1.ASYNCRAT.N. 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 this Knowledge Base page for more information.


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