Analysis by: Anthony Joe Melgarejo
 Modified by: David John Agni

ALIASES:

a variant of Win32/Bruter.C (ESET-NOD32), Trojan.Win32.Bruter (Ikarus)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may arrive bundled with malware packages as a malware component.

  TECHNICAL DETAILS

File Size: 28,672 bytes
Memory Resident: No
Initial Samples Received Date: 11 Aug 2015

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

Installation

This Trojan drops the following files:

  • %System%\xdwwiz.cpl
  • %System%\{random}.exe

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

Autostart Technique

This Trojan registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{Malware Preset Words}\Parameters
servicedll = "%Systems%\{5 or 6 random characters}.dll"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost\
{Malware Preset Words}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{Malware Preset Words}

NOTES:

It requires the following arguments to properly execute:

  • {URL where it will download the code}
  • -X
  • k3xCulobG7hnwqzy0sBb

It save the files it downloads using the following file names:

  • %Systems%\{5 or 6 random characters}.dll
  • %System%\xdwwiz.cpl

{Malware Preset Words} in the added registry keys can be any of the following:

  • Enables
  • Allows
  • Provides
  • Monitor
  • Supports
  • Audio Services
  • Basic CAPI SubSystem
  • Account Manager
  • Internet Security
  • Power Manager
  • Software Licence
  • CryptographicAPI
  • System Event Manger
  • Dailup Networking
  • Display Manager
  • Remote Access Protocol
  • ClamAV Updater
  • DNS Configuration
  • Network Fileshare
  • BitLocker Encryption
  • Secure FileSystem
  • Windows MediaPlayer

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.848.03
FIRST VSAPI PATTERN DATE: 11 Aug 2015
VSAPI OPR PATTERN File: 11.849.00
VSAPI OPR PATTERN Date: 12 Aug 2015

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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • {Malware Preset Words}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • {Malware Preset Words}

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.  
  • %System%\xdwwiz.cpl
  • %Systems%\{5 or 6 random characters}.dll

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_BRUTER.C. 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 this Knowledge Base page for more information.


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