Analysis by: Neljorn Nathaniel Aguas
 ALIASES:

Win32/InstallCore.Gen.A potentially unwanted application (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Adware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Adware 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.

It does not have any information-stealing capability.

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

Tipo de compactação: 797,584 bytes
Tipo de arquivo: EXE
Residente na memória: No
Data de recebimento das amostras iniciais: 19 Jun 2025

Arrival Details

This Adware 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 Adware drops the following files:

  • %User Temp%\{Random Hex}.log
  • %User Temp%\ish{Random Number}\css\ie6_main.css
  • %User Temp%\ish{Random Number}\css\main.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\browse.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\button.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{Random Number}\csshover3.htc
  • %User Temp%\ish{Random Number}\dat\upd.DAT
  • %User Temp%\ish{Random Number}\form.bmp.Mask
  • %User Temp%\ish{Random Number}\images\BG.png
  • %User Temp%\ish{Random Number}\images\Close.png
  • %User Temp%\ish{Random Number}\images\Close_Hover.png
  • %User Temp%\ish{Random Number}\images\Color_Button.png
  • %User Temp%\ish{Random Number}\images\Color_Button_Hover.png
  • %User Temp%\ish{Random Number}\images\Grey_Button.png
  • %User Temp%\ish{Random Number}\images\Grey_Button_Hover.png
  • %User Temp%\ish{Random Number}\images\Loader.gif
  • %User Temp%\ish{Random Number}\images\Logo.png
  • %User Temp%\ish{Random Number}\images\Progress.png
  • %User Temp%\ish{Random Number}\images\ProgressBar.png
  • %User Temp%\ish{Random Number}\images\text-bg.png
  • %User Temp%\ish{Random Number}\locale\DE.locale
  • %User Temp%\ish{Random Number}\locale\EN.locale
  • %User Temp%\ish{Random Number}\locale\ES.locale
  • %User Temp%\ish{Random Number}\locale\FR.locale
  • %User Temp%\ish{Random Number}\locale\IT.locale
  • %User Temp%\ish{Random Number}\locale\PL.locale
  • %User Temp%\ish{Random Number}\locale\PT.locale
  • %User Temp%\ish{Random Number}\locale\RU.locale
  • %User Temp%\ish{Random Number}\locale\UA.locale
  • %User Temp%\ish{Random Number}\bootstrap_23925.html
  • %Program Files%\is{Random Number}.log
  • %User Temp%\{Random Hex}.log
  • %User Temp%\ICReinstall_{Grayware Filename} → dropped copy
  • %User Temp%\{Random Hex}.log
  • %User Temp%\ish{Random Number}\{Random Number}_stp.EXE
  • %Desktop%\Continue Download Manager Installation.lnk
  • %User Temp%\ish{Random Number}\{Random Number}_stp.EXE.part

(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).. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 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).)

It adds the following processes:

  • {Malware Path}\{Malware Filename} /_ShowProgress

Propagation

This Adware does not have any propagation routine.

Backdoor Routine

This Adware does not have any backdoor routine.

Rootkit Capabilities

This Adware does not have rootkit capabilities.

Information Theft

This Adware does not have any information-stealing capability.

Other Details

This Adware connects to the following website to send and receive information:

  • http://os.{BLOCKED}wnload-manager.com/CM_DS/?v=3.0&c=1905561726
  • http://os2.{BLOCKED}wnload-manager.com/Aff-AD/?v=3.0&c=1905561726
  • http://s3.{BLOCKED}aws.com/Adlsoft/releases/DownloadManagerV2.exe
  • http://rp.{BLOCKED}wnload-manager.com/?pcrc=830800640
  • http://rp.{BLOCKED}wnload-manager.com/?pcrc=1354989342
  • http://d.{BLOCKED}.com/widget/render/hash/84d4baf304e47282405d6a04e2a11e84

It does the following:

  • It displays the following interface to install a software:
  • After installation, it creates a process to open the following URL into the default browser:
    • {Default Browser}.exe http://www.{BLOCKED}tdownload-manager.com/download-manager/welcome/oc/?&adnm=41031939867&i=s&grid=&lg=ja&cc=JP&clg=ja&c=1&d=0&cid=_781503261&kw=%E3%83%95%E3%83%AA%E3%83%BC%E3%82%BD%E3%83%95%E3%83%88&mt=&mn=all-freesoft.net&ct=&nt=D&expr=&ap=none&dv=c&agid=_72428798331&gclid=CPmL7_2rh74CFY2CvQodfIcAQA&iv=0

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

It does not exploit any vulnerability.

  SOLUTION

Mecanismo de varredura mínima: 9.800
SSAPI Pattern File: 2.849.00
SSAPI Pattern Release Date: 03 Jul 2025

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:

    • TROJ.Win32.TRX.XXPE50FSX060

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.  
  • %User Temp%\{Random Hex}.log
  • %User Temp%\ish{Random Number}\css\ie6_main.css
  • %User Temp%\ish{Random Number}\css\main.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\browse.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\button.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{Random Number}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{Random Number}\csshover3.htc
  • %User Temp%\ish{Random Number}\dat\upd.DAT
  • %User Temp%\ish{Random Number}\form.bmp.Mask
  • %User Temp%\ish{Random Number}\images\BG.png
  • %User Temp%\ish{Random Number}\images\Close.png
  • %User Temp%\ish{Random Number}\images\Close_Hover.png
  • %User Temp%\ish{Random Number}\images\Color_Button.png
  • %User Temp%\ish{Random Number}\images\Color_Button_Hover.png
  • %User Temp%\ish{Random Number}\images\Grey_Button.png
  • %User Temp%\ish{Random Number}\images\Grey_Button_Hover.png
  • %User Temp%\ish{Random Number}\images\Loader.gif
  • %User Temp%\ish{Random Number}\images\Logo.png
  • %User Temp%\ish{Random Number}\images\Progress.png
  • %User Temp%\ish{Random Number}\images\ProgressBar.png
  • %User Temp%\ish{Random Number}\images\text-bg.png
  • %User Temp%\ish{Random Number}\locale\DE.locale
  • %User Temp%\ish{Random Number}\locale\EN.locale
  • %User Temp%\ish{Random Number}\locale\ES.locale
  • %User Temp%\ish{Random Number}\locale\FR.locale
  • %User Temp%\ish{Random Number}\locale\IT.locale
  • %User Temp%\ish{Random Number}\locale\PL.locale
  • %User Temp%\ish{Random Number}\locale\PT.locale
  • %User Temp%\ish{Random Number}\locale\RU.locale
  • %User Temp%\ish{Random Number}\locale\UA.locale
  • %User Temp%\ish{Random Number}\bootstrap_23925.html
  • %Program Files%\is{Random Number}.log
  • %User Temp%\{Random Hex}.log
  • %User Temp%\ICReinstall_{Grayware Filename}
  • %User Temp%\{Random Hex}.log
  • %User Temp%\ish{Random Number}\{Random Number}_stp.EXE
  • %Desktop%\Continue Download Manager Installation.lnk
  • %User Temp%\ish{Random Number}\{Random Number}_stp.EXE.part

Step 4

Scan your computer with your Trend Micro product to delete files detected as Adware.Win32.Installcore.NLJ. 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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