Trojan.VBS.GULOADER.A


 ALIASES:

Trojan.VBS.Agent (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.

It does not have any propagation routine.

It does not have any backdoor routine.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

55,201 bytes

File Type:

VBS

Memory Resident:

No

Initial Samples Received Date:

25 Oct 2023

Payload:

Connects to URLs/IPs, Downloads 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 adds the following processes:

  • %System%\WindowsPowerShell\v1.0\powershell.exe "{Shellcode}" → If running on a 32-bit machine
  • %Windows%\SysWOW64\WindowsPowerShell\v1.0\powershell.exe "{Malware Path}\{Malware File Name}" - If running on a 64-bit machine
    • Executes the following process afterwards:
      • %Windows%\SysWOW64\WindowsPowerShell\v1.0\powershell.exe "{Shellcode}"

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

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Rootkit Capabilities

This Trojan does not have rootkit capabilities.

Download Routine

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

  • http://{BLOCKED}d.com/Udlydsk.jpb

It saves the files it downloads using the following names:

  • %Application Data%\Underbore.Gen

(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).)

Other Details

This Trojan does the following:

  • It checks if the downloaded file exists in the correct path, otherwise connect to the URL every 5 seconds.

However, as of this writing, the said sites are inaccessible.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

18.796.05

FIRST VSAPI PATTERN DATE:

03 Nov 2023

VSAPI OPR PATTERN File:

18.797.00

VSAPI OPR PATTERN Date:

04 Nov 2023

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

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%\Underbore.Gen

Step 3

Scan your computer with your Trend Micro product to delete files detected as Trojan.VBS.GULOADER.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 the following Trend Micro Support pages for more information:


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