PUA.Win32.OfferInstall.G


 ALIASES:

PUA/OfferCore.Gen (ANTIVIR)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • 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 does not have any propagation routine.

It does not have any backdoor routine.

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

  TECHNICAL DETAILS

File Size:

1,744,856 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

22 Dec 2023

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.

Installation

This Potentially Unwanted Application drops the following files:

  • %User Temp%\is-{Random Characters}.tmp\{Malware Name}.tmp → deleted afterwards
  • %User Temp%\is-{Random Characters}.tmp\file_.tmp → deleted afterwards
  • %User Temp%\is-{Random Characters}.tmp\botva2.dll → deleted afterwards
  • %User Temp%\is-{Random Characters}.tmp\Helper.dll → deleted afterwards
  • %User Temp%\is-{Random Characters}.tmp\file_.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).)

It adds the following processes:

  • "%User Temp\is-{Random Characters}.tmp\OFFERINSTALL.tmp" /SL5="$150588,832512,832512,{Malware Filename}"
  • "%User Temp\is-{Random Characters}.tmp\file_.exe" /LANG=en /NA=Rh85hR64
  • "%User Temp\is-{Random Characters}.tmp\file_.tmp" /SL5="$4305C6,1611420,832512,%User Temp%\is-{Random Characters}.tmp\file_.exe" /LANG=en /NA=Rh85hR64

(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).)

It creates the following folders:

  • %User Temp%\is-{Random Characters}.tmp\_isetup

(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).)

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.

Other Details

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

  • https://dy5wf71dvafjw.{BLOCKED}ront.net/installer/9483728320140705247/062028
  • https://server-99-84-192-220.lax3.r.{BLOCKED}ront.net

It does the following:

  • It opens a GUI prompting the user to choose one of the following languages for installation:
    • Čeština (Czech)
    • Dansk (Danish)
    • Deutsch (German)
    • English
    • Español (Spanish)
    • Français (French)
    • Italiano (Italian)
    • Nederlands (Dutch)
    • Norsk (Norwegian)
    • Polski (Polish)
    • Português Brasileiro (Brazilian Portuguese)
    • Suomi (Finnish)
    • Türkçe (Turkish)
    • Русский (Russian)
  • It displays a GUI showing the progress of the installation:
  • It displays the following message box if the malware fails to install:

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

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

SSAPI PATTERN File:

2.687.00

SSAPI PATTERN Date:

28 Dec 2023

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

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%\is-{Random Characters}.tmp\{Malware Name}.tmp
  • %User Temp%\is-{Random Characters}.tmp\file_.tmp
  • %User Temp%\is-{Random Characters}.tmp\botva2.dll
  • %User Temp%\is-{Random Characters}.tmp\Helper.dll
  • %User Temp%\is-{Random Characters}.tmp\file_.exe

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%\is-{Random Characters}.tmp\_isetup
  • %User Temp%\is-{Random Characters}.tmp

Step 5

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.OfferInstall.G. 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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