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TROJ_BHO.HK

July 25, 2013
 ALIASES:

TrojanDropper:Win32/Winbudget (Microsoft); RDN/Generic Dropper!eh (McAfee); Trojan.Adclicker (Symantec); Trojan-Dropper.Win32.Agent.hilb (Kaspersky); Trojan.Win32.Monkif.f (v) (not malicious) (Sunbelt); Trojan horse Dropper.Small.ACS (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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:

288,780 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 May 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 creates the following folders:

  • %Program Files%\Common

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This Trojan deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Ext\
Settings\{0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{D83A7B12-A4D4-4984-8F72-D41C6B4C1E6E}

Dropping Routine

This Trojan drops the following files:

  • %Program Files%\Common\helper.dll

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

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.
  • %Program Files%\Common\helper.dll

Step 3

Search and delete this folder

[ 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.
  • %Program Files%\Common

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_BHO.HK. 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.

Step 5

Restore these deleted registry keys/values from backup

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

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Ext\Settings
    • {0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {0CB66BA8-5E1F-4963-93D1-E1D6B78FE9A2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {D83A7B12-A4D4-4984-8F72-D41C6B4C1E6E}


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