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PUA_INSTALLCORE.GS

April 24, 2018
 Analysis by: Michael Jay Villanueva
 ALIASES:

PUP.Optional.InstallCore (Malwarebytes); Riskware/InstallCore (Fortinet); AdWare.Win32.DealPly.cylfj (Kaspersky)

 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:

Dropped by other malware, 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. It arrives as a component bundled with malware/grayware packages.

It does not have any propagation routine.

It does not have any backdoor routine.

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:

1,542,472 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

15 Jan 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 arrives as a component bundled with malware/grayware packages.

Installation

This Potentially Unwanted Application drops the following files:

  • %User Temp%\{random filename}.log
  • %User Temp%\in{random characters}\csshover3.htc
  • %User Temp%\in{random characters}\form.bmp.Mask
  • %User Temp%\in{random characters}\css\ie6_main.css
  • %User Temp%\in{random characters}\css\ie6_main.scss
  • %User Temp%\in{random characters}\css\main.css
  • %User Temp%\in{random characters}\css\main.scss
  • %User Temp%\in{random characters}\css\_functions.scss
  • %User Temp%\in{random characters}\css\_helpers.scss
  • %User Temp%\in{random characters}\css\_variables.scss
  • %User Temp%\in{random characters}\css\helpers\_align.scss
  • %User Temp%\in{random characters}\css\helpers\_backgrounds.scss
  • %User Temp%\in{random characters}\css\helpers\_border-radius.scss
  • %User Temp%\in{random characters}\css\helpers\_border.scss
  • %User Temp%\in{random characters}\css\helpers\_clearfix.scss
  • %User Temp%\in{random characters}\css\helpers\_colors.scss
  • %User Temp%\in{random characters}\css\helpers\_display.scss
  • %User Temp%\in{random characters}\css\helpers\_float.scss
  • %User Temp%\in{random characters}\css\helpers\_lists.scss
  • %User Temp%\in{random characters}\css\helpers\_margin.scss
  • %User Temp%\in{random characters}\css\helpers\_padding.scss
  • %User Temp%\in{random characters}\css\helpers\_positions.scss
  • %User Temp%\in{random characters}\css\helpers\_typography.scss
  • %User Temp%\in{random characters}\css\helpers\_visibility.scss
  • %User Temp%\in{random characters}\css\helpers\_width-height.scss
  • %User Temp%\in{random characters}\css\helpers\_z-index.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_browse.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_button.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_checkbox.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_progress-bar.scss
  • %User Temp%\in{random characters}\css\sdk-ui\images\button-bg.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\in{random characters}\images\BG.png
  • %User Temp%\in{random characters}\images\Close.png
  • %User Temp%\in{random characters}\images\Close_Hover.png
  • %User Temp%\in{random characters}\images\Color_Button.png
  • %User Temp%\in{random characters}\images\Color_Button_Hover.png
  • %User Temp%\in{random characters}\images\Grey_Button.png
  • %User Temp%\in{random characters}\images\Grey_Button_Hover.png
  • %User Temp%\in{random characters}\images\Icon_Generic.png
  • %User Temp%\in{random characters}\images\Loader.gif
  • %User Temp%\in{random characters}\images\Pause_Button.png
  • %User Temp%\in{random characters}\images\Progress.png
  • %User Temp%\in{random characters}\images\ProgressBar.png
  • %User Temp%\in{random characters}\images\Quick_Specs.png
  • %User Temp%\in{random characters}\images\Resume_Button.png
  • %User Temp%\in{random characters}\images\sponsored.png
  • %User Temp%\in{random characters}\locale\CS.locale
  • %User Temp%\in{random characters}\locale\DE.locale
  • %User Temp%\in{random characters}\locale\EL.locale
  • %User Temp%\in{random characters}\locale\EN.locale
  • %User Temp%\in{random characters}\locale\ES.locale
  • %User Temp%\in{random characters}\locale\FR.locale
  • %User Temp%\in{random characters}\locale\ID.locale
  • %User Temp%\in{random characters}\locale\IT.locale
  • %User Temp%\in{random characters}\locale\JA.locale
  • %User Temp%\in{random characters}\locale\NL.locale
  • %User Temp%\in{random characters}\locale\PL.locale
  • %User Temp%\in{random characters}\locale\PT.locale
  • %User Temp%\in{random characters}\locale\RU.locale
  • %User Temp%\in{random characters}\locale\TR.locale
  • %User Temp%\in{random characters}\{random filename}.tmp
  • %User Temp%\in{random characters}\bootstrap_{random}.html

(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

It creates the following folders:

  • %User Temp%\in{random characters}\css
  • %User Temp%\in{random characters}\css\helpers
  • %User Temp%\in{random characters}\css\sdk-ui
  • %User Temp%\in{random characters}\css\sdk-ui\images
  • %User Temp%\in{random characters}\images
  • %User Temp%\in{random characters}\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.)

Propagation

This Potentially Unwanted Application does not have any propagation routine.

Backdoor Routine

This Potentially Unwanted Application does not have any backdoor routine.

Rootkit Capabilities

This Potentially Unwanted Application does not have rootkit capabilities.

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://rp.{BLOCKED}iverystock.com/
  • http://os.{BLOCKED}iverystock.com/DownloadAstro/

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

It does not exploit any vulnerability.

NOTES:

This PUA 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:

1.911.00

SSAPI PATTERN Date:

18 Jan 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

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

Step 4

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 filename}.log
  • %User Temp%\in{random characters}\csshover3.htc
  • %User Temp%\in{random characters}\form.bmp.Mask
  • %User Temp%\in{random characters}\css\ie6_main.css
  • %User Temp%\in{random characters}\css\ie6_main.scss
  • %User Temp%\in{random characters}\css\main.css
  • %User Temp%\in{random characters}\css\main.scss
  • %User Temp%\in{random characters}\css\_functions.scss
  • %User Temp%\in{random characters}\css\_helpers.scss
  • %User Temp%\in{random characters}\css\_variables.scss
  • %User Temp%\in{random characters}\css\helpers\_align.scss
  • %User Temp%\in{random characters}\css\helpers\_backgrounds.scss
  • %User Temp%\in{random characters}\css\helpers\_border-radius.scss
  • %User Temp%\in{random characters}\css\helpers\_border.scss
  • %User Temp%\in{random characters}\css\helpers\_clearfix.scss
  • %User Temp%\in{random characters}\css\helpers\_colors.scss
  • %User Temp%\in{random characters}\css\helpers\_display.scss
  • %User Temp%\in{random characters}\css\helpers\_float.scss
  • %User Temp%\in{random characters}\css\helpers\_lists.scss
  • %User Temp%\in{random characters}\css\helpers\_margin.scss
  • %User Temp%\in{random characters}\css\helpers\_padding.scss
  • %User Temp%\in{random characters}\css\helpers\_positions.scss
  • %User Temp%\in{random characters}\css\helpers\_typography.scss
  • %User Temp%\in{random characters}\css\helpers\_visibility.scss
  • %User Temp%\in{random characters}\css\helpers\_width-height.scss
  • %User Temp%\in{random characters}\css\helpers\_z-index.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_browse.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_button.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_checkbox.scss
  • %User Temp%\in{random characters}\css\sdk-ui\_progress-bar.scss
  • %User Temp%\in{random characters}\css\sdk-ui\images\button-bg.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\in{random characters}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\in{random characters}\images\BG.png
  • %User Temp%\in{random characters}\images\Close.png
  • %User Temp%\in{random characters}\images\Close_Hover.png
  • %User Temp%\in{random characters}\images\Color_Button.png
  • %User Temp%\in{random characters}\images\Color_Button_Hover.png
  • %User Temp%\in{random characters}\images\Grey_Button.png
  • %User Temp%\in{random characters}\images\Grey_Button_Hover.png
  • %User Temp%\in{random characters}\images\Icon_Generic.png
  • %User Temp%\in{random characters}\images\Loader.gif
  • %User Temp%\in{random characters}\images\Pause_Button.png
  • %User Temp%\in{random characters}\images\Progress.png
  • %User Temp%\in{random characters}\images\ProgressBar.png
  • %User Temp%\in{random characters}\images\Quick_Specs.png
  • %User Temp%\in{random characters}\images\Resume_Button.png
  • %User Temp%\in{random characters}\images\sponsored.png
  • %User Temp%\in{random characters}\locale\CS.locale
  • %User Temp%\in{random characters}\locale\DE.locale
  • %User Temp%\in{random characters}\locale\EL.locale
  • %User Temp%\in{random characters}\locale\EN.locale
  • %User Temp%\in{random characters}\locale\ES.locale
  • %User Temp%\in{random characters}\locale\FR.locale
  • %User Temp%\in{random characters}\locale\ID.locale
  • %User Temp%\in{random characters}\locale\IT.locale
  • %User Temp%\in{random characters}\locale\JA.locale
  • %User Temp%\in{random characters}\locale\NL.locale
  • %User Temp%\in{random characters}\locale\PL.locale
  • %User Temp%\in{random characters}\locale\PT.locale
  • %User Temp%\in{random characters}\locale\RU.locale
  • %User Temp%\in{random characters}\locale\TR.locale
  • %User Temp%\in{random characters}\{random filename}.tmp
  • %User Temp%\in{random characters}\bootstrap_{random}.html

Step 5

Scan your computer with your Trend Micro product to delete files detected as PUA_INSTALLCORE.GS. 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 6

Reset Internet security settings

[ Learn More ]


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