TROJ_BHO.BECI

 Analysis by: Jaime Benigno Reyes

 ALIASES:

Trojan Horse (Symantec), Trojan.Win32.Vicenor (Ikarus)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

312,320 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Jan 2013

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:

  • %Application Data%\MCommon\config.dat
  • %Application Data%\MCommon\sites.dat
  • %Application Data%\MCommon\uid.dat
  • %Application Data%\MCommon\vinfo.dat
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome.manifest
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\install.rdf
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\addlist.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\em.xul
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\hashtable.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\overlay.xul
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content\update.js
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\skin\mozilla-logo.png
  • %Application Data%\WinLive\Interop.SHDocVw.dll
  • %Application Data%\WinLive\MSHTMLSubset.dll
  • %Application Data%\WinLive\WinLive.dll
  • %User Temp%\extractlive.exe
  • %User Temp%\MTemp\chrome.manifest
  • %User Temp%\MTemp\chrome\content\addlist.js
  • %User Temp%\MTemp\chrome\content\em.xul
  • %User Temp%\MTemp\chrome\content\hashtable.js
  • %User Temp%\MTemp\chrome\content\overlay.xul
  • %User Temp%\MTemp\chrome\content\update.js
  • %User Temp%\MTemp\chrome\skin\mozilla-logo.png
  • %User Temp%\MTemp\ActivatorIE.exe
  • %User Temp%\MTemp\ie9lib.dll
  • %User Temp%\MTemp\install.rdf
  • %User Temp%\MTemp\Interop.SHDocVw.dll
  • %User Temp%\MTemp\MSHTMLSubset.dll
  • %User Temp%\MTemp\WinLive.dll

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It creates the following folders:

  • %Application Data%\MCommon
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\content
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix\chrome\skin
  • %Application Data%\WinLive
  • %User Temp%\MTemp
  • %User Temp%\MTemp\chrome
  • %User Temp%\MTemp\chrome\content
  • %User Temp%\MTemp\chrome\skin

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

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\{2adefb8e-b923-35e6-86e2-2b7841f5d2a2}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\IE.PerformancePack

HKEY_CLASSES_ROOT\CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
IE.PerformancePack

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Approved Extensions
{2ADEFB8E-B923-35e6-86E2-2B7841F5D2A2} = "{value}"

HKEY_CURRENT_USER\Software\Mozilla\
Firefox\Extensions
hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"

It modifies the Internet Explorer Privacy Settings.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.662.04

FIRST VSAPI PATTERN DATE:

17 Jan 2013

VSAPI OPR PATTERN File:

9.663.00

VSAPI OPR PATTERN Date:

18 Jan 2013

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

Restart in Safe Mode

[ Learn More ]

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.

  • HKEY_CLASSES_ROOT\IE.PerformancePack
  • HKEY_CLASSES_ROOT\CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\IE.PerformancePack
  • HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{2ADEFB8E-B923-35E6-86E2-2B7841F5D2A2}
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{2adefb8e-b923-35e6-86e2-2b7841f5d2a2}

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_CURRENT_USER\Software\Mozilla\Firefox\Extensions
    • hotfix@mozilla.org = "%Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Approved Extensions
    • {2ADEFB8E-B923-35e6-86E2-2B7841F5D2A2} = "{value}"

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%\extractlive.exe

Step 6

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.
  • %Application Data%\MCommon
  • %Application Data%\Mozilla\Firefox\Extensions\MozillaHotfix
  • %Application Data%\WinLive
  • %User Temp%\MTemp

Step 7

Reset Internet privacy settings

[ Learn More ]

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_BHO.BECI. 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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