Trojan.VBS.DLOADR.PYICEKCM

May 15, 2021
 Analysis by: Mc Justine De Guzman
 ALIASES:

Trojan-Downloader.VBS.Agent.bbf (KASPERSKY)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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:

6,350 bytes

File Type:

VBS

Memory Resident:

No

Initial Samples Received Date:

11 Apr 2021

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 folders:

  • %Public%\{Computer name}

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

It adds the following processes:

  • {Malware full path} uac -> if it is ran without an argument
  • %System%\shutdown.exe -r -t 1500

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

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
{Computer name} = "regsvr32.exe "%Public%\{Computer name}\{Computer name}p.jpg""

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

Dropping Routine

This Trojan drops the following files:

  • %Public%\{Computer name}\id -> contains "al"

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}.250.168/xsm/al/132.txt -> if victim's machine is 32 bit
  • http://{BLOCKED}.{BLOCKED}.250.168/xsm/al/232.txt -> if victim's machine is 32 bit
  • http://{BLOCKED}.{BLOCKED}.250.168/xsm/al/164.txt -> if victim's machine is 64 bit
  • http://{BLOCKED}.{BLOCKED}.250.168/xsm/al/264.txt -> if victim's machine is 64 bit
  • http://{BLOCKED}.{BLOCKED}.250.168/xsm/al/6.txt

It saves the files it downloads using the following names:

  • %Public%\{Computer name}\{Computer name}p.jpg
  • %Public%\{Computer name}\{Computer name}.jpg
  • %Public%\{Computer name}\{Computer name}pl.jpg

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

16.718.06

FIRST VSAPI PATTERN DATE:

14 May 2021

VSAPI OPR PATTERN File:

16.719.00

VSAPI OPR PATTERN Date:

15 May 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:

     
    • Downloader.VBS.TRX.XXVBS82EFF012

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

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • {Computer name} = "regsvr32.exe  "%Public%\{Computer name}\{computer name}p.jpg""

Step 5

Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • EnableLUA = 0

Step 6

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.
  • %Public%\{Computer name}\{Computer name}p.jpg
  • %Public%\{Computer name}\{Computer name}.jpg
  • %Public%\{Computer name}\{Computer name}pl.jpg

Step 7

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.
  • %Public%\{Computer name}

Step 8

Scan your computer with your Trend Micro product to delete files detected as Trojan.VBS.DLOADR.PYICEKCM. 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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