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PUA.Win32.InstallCore.USMANHOBCY

October 09, 2019
 Analysis by: Warren Adam Sto. Tomas
 ALIASES:

PUA/InstallCo.bems (AntiVir); Win32/InstallCore.Gen.A (Nod32)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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.

  TECHNICAL DETAILS

File Size:

809,568 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 Oct 2019

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:

  • %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}\dat\upd.DAT
  • %User Temp%\ish{random numbers}\form.bmp.Mask
  • %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\Loader.gif
  • %User Temp%\ish{random numbers}\images\Logo.png
  • %User Temp%\ish{random numbers}\images\Progress.png
  • %User Temp%\ish{random numbers}\images\ProgressBar.png
  • %User Temp%\ish{random numbers}\images\text-bg.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\PL.locale
  • %User Temp%\ish{random numbers}\locale\PT.locale
  • %User Temp%\ish{random numbers}\locale\RU.locale
  • %User Temp%\ish{random numbers}\locale\UA.locale
  • %User Temp%\ish{random numbers}\bootstrap_{random numbers}.html
  • %User Temp%\ICReinstall_tset.exe
  • %User Temp%\is{numbers}\{numbers}_stp.EXE_stp.EXE
  • %Desktop%\Continue File Opener Installation.lnk
  • %User Temp%\is{numbers}\{numbers}_stp.EXE.part
  • %User Temp%\{random numbers}.{random numbers}_Update.exe
  • %Program Files%\is{random numbers}.log
  • %User Temp%\{random hex numbers}.log

(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).. %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).)

It adds the following processes:

  • {malware file path and name} /_ShowProgress
  • %User Temp%\{random numbers}.{random numbers}_Update.exe /install /ProdName="Extended Update" /unnm="Extended Update"
  • iexplore.exe http://th{BLOCKED}r.com/file-opener/welcome/oc/?iv=0

It creates 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}\dat
  • %User Temp%\ish{random numbers}\images
  • %User Temp%\ish{random numbers}\locale

(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).)

Other Details

This Potentially Unwanted Application connects to the following possibly malicious URL:

  • http://rp.co{BLOCKED}er.com/?pcrc=1434352513&v=2.0
  • http://os.th{BLOCKED}r.com/CM_DS/?v=5.0&c=481480170
  • http://s3.a{BLOCKED}s.com/Tweaks/distros/FileOpenerSetupG.exe
  • http://su{BLOCKED}les.com/
  • http://os2.th{BLOCKED}r.com/CM_DS/?v=5.0&c=481480170
  • http://rp.th{BLOCKED}r.com/?pcrc=83919695&v=2.0
  • http://rp.th{BLOCKED}r.com/?pcrc=1952257177&v=2.0

  SOLUTION

Minimum Scan Engine:

9.850

SSAPI PATTERN File:

2.223.00

SSAPI PATTERN Date:

10 Oct 2019

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.USMANHOBCY

[ 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%\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}\dat
  • %User Temp%\ish{random numbers}\images
  • %User Temp%\ish{random numbers}\locale
  • %User Temp%\is{numbers}

Step 5

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%\ICReinstall_tset.exe
  • %Desktop%\Continue File Opener Installation.lnk
  • %User Temp%\{random numbers}.{random numbers}_Update.exe
  • %Program Files%\is{random numbers}.log
  • %User Temp%\{random hex numbers}.log

Step 6

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