PUA.Win32.Installcore.USMANHOBVO

 Analysis by: Paul Steven Nadera

 ALIASES:

a variant of Win32/InstallCore.BQ potentially unwanted application (NOD32): InstallCore (fs) (Sunbelt)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


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.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

1,278,400 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Nov 2020

Payload:

Connects to URLs/IPs, Displays windows

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 drops the following files:

  • %Desktop%\Continue PDF Writer Installation.lnk
  • %User Temp%\is{random characters}\blank.gif
  • %User Temp%\is{random characters}\css\buttons.css
  • %User Temp%\is{random characters}\css\ie6_main.css
  • %User Temp%\is{random characters}\css\main.css
  • %User Temp%\is{random characters}\css\sdk-ui\browse.css
  • %User Temp%\is{random characters}\css\sdk-ui\button.css
  • %User Temp%\is{random characters}\css\sdk-ui\checkbox.css
  • %User Temp%\is{random characters}\css\sdk-ui\images\button-bg.png
  • %User Temp%\is{random characters}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\is{random characters}\css\sdk-ui\progress-bar.css
  • %User Temp%\is{random characters}\DAT\DSiteU.dat
  • %User Temp%\is{random characters}\images\back-button.png
  • %User Temp%\is{random characters}\images\back-over.png
  • %User Temp%\is{random characters}\images\back.png
  • %User Temp%\is{random characters}\images\Bg.gif
  • %User Temp%\is{random characters}\images\close-button.png
  • %User Temp%\is{random characters}\images\finish-button.png
  • %User Temp%\is{random characters}\images\icon.png
  • %User Temp%\is{random characters}\images\loader.gif
  • %User Temp%\is{random characters}\images\next-button-disabled.png
  • %User Temp%\is{random characters}\images\next-button-es.png
  • %User Temp%\is{random characters}\images\next-button-over.png
  • %User Temp%\is{random characters}\images\next-button.png
  • %User Temp%\is{random characters}\images\progress-bg.png
  • %User Temp%\is{random characters}\images\Progress.png
  • %User Temp%\is{random characters}\images\ProgressBar.png
  • %User Temp%\is{random characters}\license\DE.license.txt
  • %User Temp%\is{random characters}\license\EN.license.txt
  • %User Temp%\is{random characters}\locale\EN.locale
  • %User Temp%\is{random characters}\sdk\exceptlist.txt
  • %User Temp%\is{random characters}\bootstrap_8164.html
  • C:\Program Files\is{random characters}.log
  • %User Temp%\{random characters}.log
  • %User Temp%\ICReinstall_{grayware filename}.exe
  • %User Temp%\is{random characters}\{random characters}.cfg
  • %User Temp%\is{random characters}\{random numbers}_Setup.CIS
  • %User Temp%\{random numbers}_Update.exe

(Note: %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).. %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 adds the following processes:

  • "%User Temp%\{random numbers}_Update.exe" /install /ProdName="PDF Writer" /unnm="Update for PDF Writer"
  • %System%\cmd.exe /d /c TIMEOUT 3 & cmd /d /c cmd /d /c cmd /d /c cmd /d /c cmd /d /c del "%User Temp%\{random numbers}_Update.EXE"

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

Other System Modifications

This Potentially Unwanted Application adds the following registry entries:

HKEY_CURRENT_USER\Software\InstallCore\
Uninstall\{random characters}
uninstall = {random characters}

HKEY_CURRENT_USER\Software\InstallCore\
Uninstall\{random characters}
add_desc = {random characters}

HKEY_CURRENT_USER\Software\InstallCore\
Uninstall\{random characters}
add_link = {random characters}

Download Routine

This Potentially Unwanted Application accesses the following websites to download files:

  • http://os.{BLOCKED}converter.com/v1.0.1/?v=3.0&c={random numbers}
  • http://cdneu.{BLOCKED}converter.com/app/Cmp/PDFCreatorV4.cis
  • http://cdnus.{BLOCKED}converter.com/app/Cmp/PDFCreatorV4.cis
  • http://cdneu.{BLOCKED}converter.com/ofr/DealPly/Dealply.cis
  • http://cdnus.{BLOCKED}converter.com/ofr/DealPly/Dealply.cis

As of this writing, the said sites are inaccessible.

Other Details

This Potentially Unwanted Application adds the following registry keys:

HKEY_CURRENT_USER\Software\InstallCore

HKEY_CURRENT_USER\Software\InstallCore\
Uninstall

HKEY_CURRENT_USER\Software\InstallCore\
Uninstall\{random characters}

It displays the following images:

  SOLUTION

Minimum Scan Engine:

9.800

SSAPI PATTERN File:

2.353.00

SSAPI PATTERN Date:

12 Nov 2020

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

Identify and terminate files detected as PUA.Win32.Installcore.USMANHOBVO

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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_CURRENT_USER\Software\InstallCore\Uninstall\{random characters}
    • uninstall = {random characters}
  • In HKEY_CURRENT_USER\Software\InstallCore\Uninstall\{random characters}
    • add_desc = {random characters}
  • In HKEY_CURRENT_USER\Software\InstallCore\Uninstall{random characters}
    • add_link = {random characters}

Step 5

Delete this registry key

[ 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.

  • HKEY_CURRENT_USER\Software\InstallCore
  • HKEY_CURRENT_USER\Software\InstallCore\Uninstall
  • HKEY_CURRENT_USER\Software\InstallCore\Uninstall\{random characters}

Step 6

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.

Step 7

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.Installcore.USMANHOBVO. 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:


Did this description help? Tell us how we did.