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PUA.Win32.HostChanger.B

February 05, 2020
 ALIASES:

Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 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:

476,173 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Feb 2020

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 adds the following processes:

  • net session
  • reg delete "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019" /va /f
  • %System%\find.exe FIND /C /I "on4u3.buhl.de" %System%\drivers\etc\hosts
  • %System%\find.exe FIND /C /I "www.on4u3.buhl.de" %System%\drivers\etc\hosts
  • %System%\find.exe FIND /C /I "drm.buhl.de" %System%\drivers\etc\hosts
  • %System%\find.exe FIND /C /I "www.drm.buhl.de" %System%\drivers\etc\hosts
  • reg export "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019" "%Application Data%\Buhl\WISO steuer-Sparbuch\2019\WISO.reg"
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private" /v ErsterProgrammstart /d "0" /t REG_SZ /f
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User" /v InetUpdateQuietAutoCheck /d "0" /t REG_SZ /f
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User" /v InetUpdateQuietAutoCheckStatus /d "0x0002560f" /t REG_SZ /f
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User" /v InetUpdateAutoCheck /d "3171" /t REG_SZ /f
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private" /v LastupdatecheckProgram /d "Thu 10/03/2019" /t REG_SZ /f
  • reg add "HKCU\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private" /v UpdateStatus /d "lokale Version ist aktuell" /t REG_SZ /f
  • %System%\net1 session

It creates the following folders:

  • %User Profile%\AppData
  • %User Temp%\RarSFX0
  • %System Root%\Users

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} 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).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other System Modifications

This Potentially Unwanted Application modifies the following file(s):

  • %System%\drivers\etc\hosts

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

It deletes the following folders:

  • %All Users Profile%\Buhl Data Service GmbH

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\Private
ErsterProgrammstart = "0"

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\User
InetUpdateQuietAutoCheck = "0"

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\User
InetUpdateQuietAutoCheckStatus = "0x0002560f"

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\User
InetUpdateAutoCheck = "3171"

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\Private
LastupdatecheckProgram = "Thu 10/03/2019"

HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\
WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\
Profil\Private
UpdateStatus = "lokale Version ist aktuell"

Dropping Routine

This Potentially Unwanted Application drops the following files:

  • %Desktop%\daily WISO Patch.lnk
  • %Application Data%\Buhl\WISO steuer-Sparbuch\2019
  • %User Temp%\RarSFX0\wiso.ico
  • %User Temp%\RarSFX0\WISO.reg

(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).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming 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).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

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

Identify and terminate files detected as PUA.Win32.HostChanger.B

[ 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 3

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\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private
    • ErsterProgrammstart = "0"
  • In HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User
    • InetUpdateQuietAutoCheck = "0"
  • In HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User
    • InetUpdateQuietAutoCheckStatus = "0x0002560f"
  • In HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\User
    • InetUpdateAutoCheck = "3171"
  • In HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private
    • LastupdatecheckProgram = "Thu 10/03/2019"
  • In HKEY_CURRENT_USER\Software\Buhl Data Service GmbH\WISO Sparbuch\WISO steuer:Sparbuch 2019\Optionen\Profil\Private
    • UpdateStatus = "lokale Version ist aktuell"

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Desktop%\daily WISO Patch.lnk
  • %Application Data%\Buhl\WISO steuer-Sparbuch\2019
  • %User Temp%\RarSFX0\wiso.ico
  • %User Temp%\RarSFX0\WISO.reg

Step 5

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 Profile%\AppData
  • %User Temp%\RarSFX0
  • %System Root%\Users

Step 6

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.HostChanger.B. 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

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %System%\drivers\etc\hosts


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