Analysis by: Mohammed Malubay
 ALIASES:

a variant of Win32/InstallCore.BK.gen potentially unwanted application(NOD32);

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Canal de infecção: Downloaded from the Internet, Dropped by other malware

This Potentially Unwanted Application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It connects to certain websites to send and receive information. It redirects browsers to certain sites.

  TECHNICAL DETAILS

Tipo de compactação: 594,864 bytes
Tipo de arquivo: EXE
Data de recebimento das amostras iniciais: 02 Apr 2021
Carga útil: Connects to URLs/IPs, Displays graphics/image, Drops files

Arrival Details

This Potentially Unwanted Application 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 Potentially Unwanted Application adds the following folders:

  • %User Temp%\ish{random numbers}
  • %User Temp%\ish{random numbers}\css
  • %User Temp%\ish{random numbers}\css\sdk-ui
  • %User Temp%\ish{random numbers}\css\sdk-ui\images
  • %User Temp%\ish{random numbers}\images
  • %User Temp%\ish{random numbers}\locale
  • %User Temp%\is{random numbers}

(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).)

It drops the following files:

  • %User Temp%\{random characters}.log
  • %User Temp%\ish{random numbers}\css\ie6_main.css
  • %User Temp%\ish{random numbers}\css\main.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\browse.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\button.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{random numbers}\csshover3.htc
  • %User Temp%\ish{random numbers}\form.bmp.Mask
  • %User Temp%\ish{random numbers}\images\BG.png
  • %User Temp%\ish{random numbers}\images\Close.png
  • %User Temp%\ish{random numbers}\images\Close_Hover.png
  • %User Temp%\ish{random numbers}\images\Color_Button.png
  • %User Temp%\ish{random numbers}\images\Color_Button_Hover.png
  • %User Temp%\ish{random numbers}\images\Grey_Button.png
  • %User Temp%\ish{random numbers}\images\Grey_Button_Hover.png
  • %User Temp%\ish{random numbers}\images\Icon_Generic.png
  • %User Temp%\ish{random numbers}\images\Loader.gif
  • %User Temp%\ish{random numbers}\images\Pause_Button.png
  • %User Temp%\ish{random numbers}\images\Progress.png
  • %User Temp%\ish{random numbers}\images\ProgressBar.png
  • %User Temp%\ish{random numbers}\images\Quick_Specs.png
  • %User Temp%\ish{random numbers}\images\Resume_Button.png
  • %User Temp%\ish{random numbers}\images\Sponsored-Offer.png
  • %User Temp%\ish{random numbers}\locale\DE.locale
  • %User Temp%\ish{random numbers}\locale\EN.locale
  • %User Temp%\ish{random numbers}\locale\ES.locale
  • %User Temp%\ish{random numbers}\locale\FR.locale
  • %User Temp%\ish{random numbers}\locale\IT.locale
  • %User Temp%\ish{random numbers}\locale\JA.locale
  • %User Temp%\ish{random numbers}\locale\NL.locale
  • %User Temp%\ish{random numbers}\locale\PL.locale
  • %User Temp%\ish{random numbers}\locale\PT.locale
  • %User Temp%\ish{random numbers}\locale\RU.locale
  • %User Temp%\ish{random numbers}\bootstrap_{random numbers}.html
  • %User Temp%\ICReinstall_{Malware Filename}.exe
  • %User Temp%\is{random numbers}\{random numbers}_stp.EXE
  • %User Temp%\is{random numbers}\{random numbers}_stp.EXE.part
  • %Desktop%\Continue Vlc Media Player Installation.lnk

(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).. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Potentially Unwanted Application connects to the following website to send and receive information:

  • http://os.{BLOCKED}ritcdn.com/ForumerIT_Adwords/?v=3.0&c=370382921
  • http://os2.{BLOCKED}ritcdn.com/ForumerIT_Adwords/?v=3.0&c=370382921

It displays the following images:

It redirects browsers to the following sites:

  • https://{BLOCKED}dia-player.jp.{BLOCKED}ad.it/

It accesses the following websites to download its configuration/component files:

  • http://{BLOCKED}a.{BLOCKED}n.com/JP/vlc-media-player.exe

  SOLUTION

Mecanismo de varredura mínima: 9.800
SSAPI Pattern File: 2.397.00
SSAPI Pattern Release Date: 08 Apr 2021

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 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.
  • %User Temp%\{random characters}.log
  • %User Temp%\ish{random numbers}\css\ie6_main.css
  • %User Temp%\ish{random numbers}\css\main.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\browse.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\button.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{random numbers}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{random numbers}\csshover3.htc
  • %User Temp%\ish{random numbers}\form.bmp.Mask
  • %User Temp%\ish{random numbers}\images\BG.png
  • %User Temp%\ish{random numbers}\images\Close.png
  • %User Temp%\ish{random numbers}\images\Close_Hover.png
  • %User Temp%\ish{random numbers}\images\Color_Button.png
  • %User Temp%\ish{random numbers}\images\Color_Button_Hover.png
  • %User Temp%\ish{random numbers}\images\Grey_Button.png
  • %User Temp%\ish{random numbers}\images\Grey_Button_Hover.png
  • %User Temp%\ish{random numbers}\images\Icon_Generic.png
  • %User Temp%\ish{random numbers}\images\Loader.gif
  • %User Temp%\ish{random numbers}\images\Pause_Button.png
  • %User Temp%\ish{random numbers}\images\Progress.png
  • %User Temp%\ish{random numbers}\images\ProgressBar.png
  • %User Temp%\ish{random numbers}\images\Quick_Specs.png
  • %User Temp%\ish{random numbers}\images\Resume_Button.png
  • %User Temp%\ish{random numbers}\images\Sponsored-Offer.png
  • %User Temp%\ish{random numbers}\locale\DE.locale
  • %User Temp%\ish{random numbers}\locale\EN.locale
  • %User Temp%\ish{random numbers}\locale\ES.locale
  • %User Temp%\ish{random numbers}\locale\FR.locale
  • %User Temp%\ish{random numbers}\locale\IT.locale
  • %User Temp%\ish{random numbers}\locale\JA.locale
  • %User Temp%\ish{random numbers}\locale\NL.locale
  • %User Temp%\ish{random numbers}\locale\PL.locale
  • %User Temp%\ish{random numbers}\locale\PT.locale
  • %User Temp%\ish{random numbers}\locale\RU.locale
  • %User Temp%\ish{random numbers}\bootstrap_{random numbers}.html
  • %User Temp%\ICReinstall_{Malware Filename}.exe
  • %User Temp%\is{random numbers}\{random numbers}_stp.EXE
  • %User Temp%\is{random numbers}\{random numbers}_stp.EXE.part
  • %Desktop%\Continue Vlc Media Player Installation.lnk

Step 4

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%\ish{random numbers}
  • %User Temp%\ish{random numbers}\css
  • %User Temp%\ish{random numbers}\css\sdk-ui
  • %User Temp%\ish{random numbers}\css\sdk-ui\images
  • %User Temp%\ish{random numbers}\images
  • %User Temp%\ish{random numbers}\locale
  • %User Temp%\is{random numbers}

Step 5

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.InstallCore.MANHOBVL. 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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