Analysis by: John Rainier Navato
 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • 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 executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 30,783 bytes
File Type: JS
Memory Resident: Yes
Initial Samples Received Date: 27 Mar 2026
Payload: Connects to URLs/IPs, Drops files, Steals information

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:

  • %AppData%\temp.txt → contains 8 random characters victim ID

It creates the following folders:

  • %User Temp%\{timestamp} → contains dropped files received from the C2 server

(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).)

Autostart Technique

This Backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
electron.app.Boost Note - Local = %AppDataLocal%\UltraWareUltraCore\boosten.exe

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Arbitrary JavaScript/Node.js code execution
  • File drop and executable launch

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

  • https://{BLOCKED}spolicia.com/e702da9c5a58/o/

It posts the following information to its command and control (C&C) server:

  • Randomly generated 8-character victim identifier
  • Computer name
  • Username
  • Campaign identifier → read from {Malware File Path}\readme.txt

Other Details

This Backdoor does the following:

  • It replaces the following console methods with non-operational functions to suppress all debug output:
    • console.log
    • console.warn
    • console.info
    • console.error
    • console.exception
    • console.table
    • console.trace
  • It implements anti-debugging by executing a toString() recursion trap that uses Regular Expression Denial of Service pattern
  • It can receive base64-encoded files from the C2 server, writes them to a timestamped folder in %User Temp%\{timestamp}\, and automatically executes any file with an .exe extension

(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).)

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 20.848.08
FIRST VSAPI PATTERN DATE: 27 Mar 2026
VSAPI OPR PATTERN File: 20.849.00
VSAPI OPR PATTERN Date: 28 Mar 2026

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

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\Windows\CurrentVersion\Run
    • electron.app.Boost Note - Local = %AppDataLocal%\UltraWareUltraCore\boosten.exe

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.
  • %AppData%\temp.txt

    • Step 6

    Search and delete this folder

    [ Learn More ]
    Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\{timestamp}

    • Step 7

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


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