JS_BASYO.A

 Analysis by: Jennifer Gumban

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Worm 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:

(varies) bytes

File Type:

HTA, JS

Memory Resident:

No

Initial Samples Received Date:

30 May 2017

Arrival Details

This Worm 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 Worm drops the following copies of itself into the affected system:

  • %User Profile%\PrintHood\Agregar Impresora.hta
  • %User Startup%\Agregar Impresora.hta

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It adds the following processes:

  • wmplayer.exe

It searches for the following folders where it can drop/create files:

  • %User Profile%
  • %User Startup%

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Propagation

This Worm drops copies of itself in the following drives:

  • It propagates from drives C to Z after 60 seconds.

Other Details

This Worm does the following:

  • It creates the following shortcut files pointing to the malware copy:
    • Videos comicos.mpg.lnk
    • (Vacío).lnk
    • Agregar Impresora.lnk
  • It copies the icon of shortcut files from the following file:
    • %Program Files%\Windows Media Player\wmplayer.exe
    • %SystemRoot%\\system32\\shell32.dll, 51

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.438.06

FIRST VSAPI PATTERN DATE:

30 May 2017

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 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 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.  
  • Videos comicos.mpg.lnk
  • (Vacío).lnk
  • Agregar Impresora.lnk

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_BASYO.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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