TROJ_BUMAT.TYI

 Analysis by: Christopher Daniel So

 ALIASES:

Trojan:Win32/Bumat!rts (Microsoft), Trojan-Dropper.Win32.Small.dog (Kaspersky), TR/BHO.vmp (AntiVir)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan drops malicious files onto the affected system. It

modifies the registry to ensure its execution every system activation.

It steals information related to the game Arad Senki, and sends the information via HTTP.

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It steals sensitive information such as user names and passwords related to certain games.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

No

Initial Samples Received Date:

15 Apr 2011

Payload:

Steals information, Drops files

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %System%\LiveHelper.dll - also detected as TROJ_BUMAT.TYI

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Autostart Technique

This Trojan registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{1442E4D0-812A-4000-80BF-CEC0DD23A43C}

HKEY_CLASSES_ROOT\LiveHelper

HKEY_CLASSES_ROOT\LiveHelper.1

HKEY_CLASSES_ROOT\CLSID\{1442E4D0-812A-4000-80BF-CEC0DD23A43C}

HKEY_CLASSES_ROOT\Interface\{F76F3EFE-748A-42F7-98A8-F6C25A7547A3}

HKEY_CLASSES_ROOT\TypeLib\{1B9CAE19-E9FB-4646-B9AC-8169B3C39D0D}

It adds the following registry entries to install itself as a Browser Helper Object (BHO):

HKEY_CLASSES_ROOT\LiveHelper
(Default) = "Windows Live Helper"

HKEY_CLASSES_ROOT\LiveHelper\CLSID
(Default) = "{1442E4D0-812A-4000-80BF-CEC0DD23A43C}"

HKEY_CLASSES_ROOT\LiveHelper\CurVer
(Default) = "LiveHelper.1"

HKEY_CLASSES_ROOT\LiveHelper.1
(Default) = "Windows Live Helper"

HKEY_CLASSES_ROOT\LiveHelper.1\CLSID
(Default) = "{1442E4D0-812A-4000-80BF-CEC0DD23A43C}"

HKEY_CLASSES_ROOT\CLSID\{1442E4D0-812A-4000-80BF-CEC0DD23A43C}\
InprocServer32
(Default) = "%System%\LiveHelper.dll"

HKEY_CLASSES_ROOT\CLSID\{1442E4D0-812A-4000-80BF-CEC0DD23A43C}\
TypeLib
(Default) = "{1B9CAE19-E9FB-4646-B9AC-8169B3C39D0D}"

HKEY_CLASSES_ROOT\Interface\{F76F3EFE-748A-42F7-98A8-F6C25A7547A3}
(Default) = "IEyeIE"

HKEY_CLASSES_ROOT\Interface\{F76F3EFE-748A-42F7-98A8-F6C25A7547A3}\
TypeLib
(Default) = "{1B9CAE19-E9FB-4646-B9AC-8169B3C39D0D}"

HKEY_CLASSES_ROOT\TypeLib\{1B9CAE19-E9FB-4646-B9AC-8169B3C39D0D}\
1.0\0\win32
(Default) = "%System%\LiveHelper.dll"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer
xInput = "login26807230"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer
xPsd = "login55242311"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer
xSUrl = "http://www.{BLOCKED}y.com/rv.asp"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer
xUrl = "http://www.arad.jp/"

Information Theft

This Trojan steals sensitive information such as user names and passwords related to the following games:

  • Arad Senki (http://www.arad.jp/)

NOTES:
It sends the gathered information via HTTP to the following URL:

  • http://www.{BLOCKED}y.com/rv.asp?{login information}
However, as of this writing, the said site is no longer accessible.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.979.00

VSAPI OPR PATTERN Date:

15 Apr 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Close all opened browser windows

Step 3

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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {1442E4D0-812A-4000-80BF-CEC0DD23A43C}
  • In HKEY_CLASSES_ROOT
    • LiveHelper
  • In HKEY_CLASSES_ROOT
    • LiveHelper.1
  • In HKEY_CLASSES_ROOT\CLSID
    • {1442E4D0-812A-4000-80BF-CEC0DD23A43C}
  • In HKEY_CLASSES_ROOT\Interface
    • {F76F3EFE-748A-42F7-98A8-F6C25A7547A3}
  • In HKEY_CLASSES_ROOT\TypeLib
    • {1B9CAE19-E9FB-4646-B9AC-8169B3C39D0D}

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • xInput="login26807230"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • xPsd="login55242311"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • xSUrl="http://www.{BLOCKED}y.com/rv.asp"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer
    • xUrl="http://www.arad.jp/"

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_BUMAT.TYI. 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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