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PUA_INSTALLCORE.GAZ

July 02, 2018
 Analysis by: John Anthony Banes
 ALIASES:

Win32/InstallCore.Gen.A (NOD32); Trojan.InstallCore (Quick Heal); W32/Install_Core.ATY (Fortinet)

 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, 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 may be manually installed by a user.

It modifies the Internet Explorer Zone Settings.

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

  TECHNICAL DETAILS

File Size:

1,687,872 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Jun 2018

Payload:

Drops files, Connects to URLs/IPs

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.

It may be manually installed by a user.

Installation

This Potentially Unwanted Application adds the following folders:

  • %User Temp%\in{random}
  • %User Temp%\inH{random}
  • %User Temp%\inH{random}\css
  • %User Temp%\inH{random}\css\helpers
  • %User Temp%\inH{random}\css\sdk-ui
  • %User Temp%\inH{random}\css\sdk-ui\images
  • %User Temp%\inH{random}\images
  • %User Temp%\inH{random}\locale

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following files:

  • %User Temp%\{random}.log
  • %User Temp%\in{random}\{random}.tmp
  • %User Temp%\inH{random}\bootstrap_45674.html
  • %User Temp%\inH{random}\css\_functions.scss
  • %User Temp%\inH{random}\css\_helpers.scss
  • %User Temp%\inH{random}\css\_variables.scss
  • %User Temp%\inH{random}\css\helpers\_align.scss
  • %User Temp%\inH{random}\css\helpers\_backgrounds.scss
  • %User Temp%\inH{random}\css\helpers\_border.scss
  • %User Temp%\inH{random}\css\helpers\_border-radius.scss
  • %User Temp%\inH{random}\css\helpers\_clearfix.scss
  • %User Temp%\inH{random}\css\helpers\_colors.scss
  • %User Temp%\inH{random}\css\helpers\_display.scss
  • %User Temp%\inH{random}\css\helpers\_float.scss
  • %User Temp%\inH{random}\css\helpers\_lists.scss
  • %User Temp%\inH{random}\css\helpers\_margin.scss
  • %User Temp%\inH{random}\css\helpers\_padding.scss
  • %User Temp%\inH{random}\css\helpers\_positions.scss
  • %User Temp%\inH{random}\css\helpers\_typography.scss
  • %User Temp%\inH{random}\css\helpers\_visibility.scss
  • %User Temp%\inH{random}\css\helpers\_width-height.scss
  • %User Temp%\inH{random}\css\helpers\_z-index.scss
  • %User Temp%\inH{random}\css\ie6_main.css
  • %User Temp%\inH{random}\css\ie6_main.scss
  • %User Temp%\inH{random}\css\main.css
  • %User Temp%\inH{random}\css\main.scss
  • %User Temp%\inH{random}\css\sdk-ui\_browse.scss
  • %User Temp%\inH{random}\css\sdk-ui\_button.scss
  • %User Temp%\inH{random}\css\sdk-ui\_checkbox.scss
  • %User Temp%\inH{random}\css\sdk-ui\_progress-bar.scss
  • %User Temp%\inH{random}\css\sdk-ui\images\button-bg.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\inH{random}\csshover3.htc
  • %User Temp%\inH{random}\form.bmp.Mask
  • %User Temp%\inH{random}\images\BG.png
  • %User Temp%\inH{random}\images\Close.png
  • %User Temp%\inH{random}\images\Close_Hover.png
  • %User Temp%\inH{random}\images\Color_Button.png
  • %User Temp%\inH{random}\images\Color_Button_Hover.png
  • %User Temp%\inH{random}\images\Grey_Button.png
  • %User Temp%\inH{random}\images\Grey_Button_Hover.png
  • %User Temp%\inH{random}\images\Icon_Generic.png
  • %User Temp%\inH{random}\images\Loader.gif
  • %User Temp%\inH{random}\images\Pause_Button.png
  • %User Temp%\inH{random}\images\Progress.png
  • %User Temp%\inH{random}\images\ProgressBar.png
  • %User Temp%\inH{random}\images\Quick_Specs.png
  • %User Temp%\inH{random}\images\Quick_Specs_small.png
  • %User Temp%\inH{random}\images\Resume_Button.png
  • %User Temp%\inH{random}\images\sponsored.png
  • %User Temp%\inH{random}\locale\CS.locale
  • %User Temp%\inH{random}\locale\DA.locale
  • %User Temp%\inH{random}\locale\DE.locale
  • %User Temp%\inH{random}\locale\EL.locale
  • %User Temp%\inH{random}\locale\EN.locale
  • %User Temp%\inH{random}\locale\ES.locale
  • %User Temp%\inH{random}\locale\FI.locale
  • %User Temp%\inH{random}\locale\FR.locale
  • %User Temp%\inH{random}\locale\ID.locale
  • %User Temp%\inH{random}\locale\IT.locale
  • %User Temp%\inH{random}\locale\JA.locale
  • %User Temp%\inH{random}\locale\KO.locale
  • %User Temp%\inH{random}\locale\NL.locale
  • %User Temp%\inH{random}\locale\NO.locale
  • %User Temp%\inH{random}\locale\PL.locale
  • %User Temp%\inH{random}\locale\PT.locale
  • %User Temp%\inH{random}\locale\RU.locale
  • %User Temp%\inH{random}\locale\SV.locale
  • %User Temp%\inH{random}\locale\TR.locale
  • %User Temp%\inH{random}\locale\ZH.locale

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following processes:

  • {malware path}\{malware filename}.exe /_ShowProgress /mnl

Web Browser Home Page and Search Page Modification

This Potentially Unwanted Application modifies the Internet Explorer Zone Settings.

Other Details

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

  • http://{BLOCKED}3.{BLOCKED}nfenac.com/

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

NOTES:
This Potentially Unwanted Application shows the following progress bar once executed:

A message box will appear, saying that a product configuration is missing:

  SOLUTION

Minimum Scan Engine:

9.850

SSAPI PATTERN File:

1.977.00

SSAPI PATTERN Date:

28 Jun 2018

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

Identify and terminate files detected as PUA_INSTALLCORE.GAZ

[ 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

Search and delete these folders

[ 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%\in{random}
  • %User Temp%\inH{random}
  • %User Temp%\inH{random}\css
  • %User Temp%\inH{random}\css\helpers
  • %User Temp%\inH{random}\css\sdk-ui
  • %User Temp%\inH{random}\css\sdk-ui\images
  • %User Temp%\inH{random}\images
  • %User Temp%\inH{random}\locale

Step 5

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}.log
  • %User Temp%\in{random}\{random}.tmp
  • %User Temp%\inH{random}\bootstrap_45674.html
  • %User Temp%\inH{random}\css\_functions.scss
  • %User Temp%\inH{random}\css\_helpers.scss
  • %User Temp%\inH{random}\css\_variables.scss
  • %User Temp%\inH{random}\css\helpers\_align.scss
  • %User Temp%\inH{random}\css\helpers\_backgrounds.scss
  • %User Temp%\inH{random}\css\helpers\_border.scss
  • %User Temp%\inH{random}\css\helpers\_border-radius.scss
  • %User Temp%\inH{random}\css\helpers\_clearfix.scss
  • %User Temp%\inH{random}\css\helpers\_colors.scss
  • %User Temp%\inH{random}\css\helpers\_display.scss
  • %User Temp%\inH{random}\css\helpers\_float.scss
  • %User Temp%\inH{random}\css\helpers\_lists.scss
  • %User Temp%\inH{random}\css\helpers\_margin.scss
  • %User Temp%\inH{random}\css\helpers\_padding.scss
  • %User Temp%\inH{random}\css\helpers\_positions.scss
  • %User Temp%\inH{random}\css\helpers\_typography.scss
  • %User Temp%\inH{random}\css\helpers\_visibility.scss
  • %User Temp%\inH{random}\css\helpers\_width-height.scss
  • %User Temp%\inH{random}\css\helpers\_z-index.scss
  • %User Temp%\inH{random}\css\ie6_main.css
  • %User Temp%\inH{random}\css\ie6_main.scss
  • %User Temp%\inH{random}\css\main.css
  • %User Temp%\inH{random}\css\main.scss
  • %User Temp%\inH{random}\css\sdk-ui\_browse.scss
  • %User Temp%\inH{random}\css\sdk-ui\_button.scss
  • %User Temp%\inH{random}\css\sdk-ui\_checkbox.scss
  • %User Temp%\inH{random}\css\sdk-ui\_progress-bar.scss
  • %User Temp%\inH{random}\css\sdk-ui\images\button-bg.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\inH{random}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\inH{random}\csshover3.htc
  • %User Temp%\inH{random}\form.bmp.Mask
  • %User Temp%\inH{random}\images\BG.png
  • %User Temp%\inH{random}\images\Close.png
  • %User Temp%\inH{random}\images\Close_Hover.png
  • %User Temp%\inH{random}\images\Color_Button.png
  • %User Temp%\inH{random}\images\Color_Button_Hover.png
  • %User Temp%\inH{random}\images\Grey_Button.png
  • %User Temp%\inH{random}\images\Grey_Button_Hover.png
  • %User Temp%\inH{random}\images\Icon_Generic.png
  • %User Temp%\inH{random}\images\Loader.gif
  • %User Temp%\inH{random}\images\Pause_Button.png
  • %User Temp%\inH{random}\images\Progress.png
  • %User Temp%\inH{random}\images\ProgressBar.png
  • %User Temp%\inH{random}\images\Quick_Specs.png
  • %User Temp%\inH{random}\images\Quick_Specs_small.png
  • %User Temp%\inH{random}\images\Resume_Button.png
  • %User Temp%\inH{random}\images\sponsored.png
  • %User Temp%\inH{random}\locale\CS.locale
  • %User Temp%\inH{random}\locale\DA.locale
  • %User Temp%\inH{random}\locale\DE.locale
  • %User Temp%\inH{random}\locale\EL.locale
  • %User Temp%\inH{random}\locale\EN.locale
  • %User Temp%\inH{random}\locale\ES.locale
  • %User Temp%\inH{random}\locale\FI.locale
  • %User Temp%\inH{random}\locale\FR.locale
  • %User Temp%\inH{random}\locale\ID.locale
  • %User Temp%\inH{random}\locale\IT.locale
  • %User Temp%\inH{random}\locale\JA.locale
  • %User Temp%\inH{random}\locale\KO.locale
  • %User Temp%\inH{random}\locale\NL.locale
  • %User Temp%\inH{random}\locale\NO.locale
  • %User Temp%\inH{random}\locale\PL.locale
  • %User Temp%\inH{random}\locale\PT.locale
  • %User Temp%\inH{random}\locale\RU.locale
  • %User Temp%\inH{random}\locale\SV.locale
  • %User Temp%\inH{random}\locale\TR.locale
  • %User Temp%\inH{random}\locale\ZH.locale

Step 6

Scan your computer with your Trend Micro product to delete files detected as PUA_INSTALLCORE.GAZ. 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:

Step 7

Reset Internet security settings

[ Learn More ]


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