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Trojan.JS.GOOTLOADER.AJ

March 06, 2025
 Analysis by: Paolo Ronniel Labrador
 ALIASES:

Trojan.JS.Cryxos (IKARUS)

 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, Dropped by other malware


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:

14,583,045 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

26 Feb 2025

Payload:

Connects to URLs/IPs, 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:

  • %Application Data%\{any existing folder}\Building Strong Referral Networks.dat → renames to British Standards.js
  • %User Temp%\{random}.{random}.ps1 → deleted afterwards
  • %User Temp%\{random}.{random}.psm1 → deleted afterwards

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %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 processes:

  • %System%\cscript.exe powershell

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

Other Details

This Trojan connects to the following possibly malicious URL:

  • https://{BLOCKED}r.com
  • https://{BLOCKED}ulator.ru
  • https://{BLOCKED}nce-marketplace.com
  • https://{BLOCKED}dinsdedylan.fr
  • https://{BLOCKED}t.com
  • https://{BLOCKED}stoicism.com
  • https:/{BLOCKED}online.mcs.it
  • https://{BLOCKED}duo.com
  • https://{BLOCKED}s.pk
  • https://{BLOCKED}gretchen.com

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.930.01

FIRST VSAPI PATTERN DATE:

27 Feb 2025

VSAPI OPR PATTERN File:

19.931.00

VSAPI OPR PATTERN Date:

28 Feb 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

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.  
  • %Application Data%\{any existing folder}\Building Strong Referral Networks.dat
  • %Application Data%\{any existing folder}\British Standards.js
  • %User Temp%\{random}.{random}.ps1
  • %User Temp%\{random}.{random}.psm1

Step 4

Scan your computer with your Trend Micro product to clean files detected as Trojan.JS.GOOTLOADER.AJ. 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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