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TROJ_QHOST.AEF

October 13, 2012
 ALIASES:

Trojan.Win32.Generic!BT (Sunbelt)

 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:

40,960 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 Jun 2012

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.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings

HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\
WINDOWS\CUR RENTVERSION\RUN

HKEY_CURRENT_USER\SOFTWARE\Policies\
Microsoft\Internet Explorer\Control Panel

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
JITDebug = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CUR RENTVERSION\RUN
{malware file name} = "%System Root%\{malware file name}.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
StartPage = "http://www.{BLOCKED}raa.com"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
SearchPage = "http://www.{BLOCKED}raa.com"

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Internet Explorer\Control Panel
HomePage = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}raa.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}raa.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

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_CURRENT_USER\Software\Microsoft\Windows Script
    • Settings
  • In HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS\CUR RENTVERSION
    • RUN
  • In HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Internet Explorer
    • Control Panel

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\Microsoft\Windows Script\Settings
    • JITDebug = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CUR RENTVERSION\RUN
    • {malware file name} = "%System Root%\{malware file name}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • StartPage = "http://www.{BLOCKED}raa.com"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • SearchPage = "http://www.{BLOCKED}raa.com"
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Control Panel
    • HomePage = "0"

Step 4

Restore this modified 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\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}raa.com"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Search Page = "http://www.{BLOCKED}raa.com"
      To: Search Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_QHOST.AEF. 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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