Analysis by: Mark Joseph Manahan

ALIASES:

W32/StartPage.OOW (Fortinet), Trojan.Win32.StartPage (Ikarus), Trojan:Win32/Startpage.UY (Microsoft), Win32/StartPage.OOW trojan (Eset), 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

Infection Channel: Dropped by other malware, Downloaded from the Internet

This Trojan may be dropped by other malware.

It executes then deletes itself afterward.

It modifies the user's Internet Explorer home page into a certain website. This action allows the malware to point to a website which may contain malware, putting the affected computer at greater risk of malware infection.

  TECHNICAL DETAILS

File Size: 140,800 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 23 Nov 2012

Arrival Details

This Trojan may be dropped by the following malware:

  • JS_DLOADR.AET

It may be downloaded from the following remote sites:

  • http://{BLOCKED}browserupdate/install.exe

Installation

This Trojan drops the following files:

  • %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}.default\searchplugins\EcoStartPage.xml

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

It drops the following copies of itself into the affected system:

  • %User Temp%\suicide.exe

(Note: %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:

  • %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}.default\searchplugins

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

It executes then deletes itself afterward.

Web Browser Home Page and Search Page Modification

This Trojan modifies the user's Internet Explorer home page to the following websites:

  • http://{BLOCKED}rtpage.com

NOTES:

For Opera browser:

It modifies the file %User Profile%\Application Data\Opera\operaprefs.ini to the following:

[User Prefs]
Home URL= http://{BLOCKED}rtpage.com

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.544.04
FIRST VSAPI PATTERN DATE: 23 Nov 2012
VSAPI OPR PATTERN File: 9.545.00
VSAPI OPR PATTERN Date: 24 Nov 2012

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

Remove the malware/grayware file that dropped/downloaded TROJ_STARTPA.AET

Step 3

Reset the Internet Explorer Home and Search pages

[ Learn More ]

Step 4

Search and delete this file

[ Learn More ]
There may be some component 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 Profile%\Application Data\Mozilla\Firefox\Profiles\{random}.default\searchplugins\EcoStartPage.xml

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_STARTPA.AET. 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.

NOTES:

Please perform this before step 4.

For restoring Opera hompage

  1. Open %User Profile%\Application Data\Opera\Opera\operaprefs.ini using Notepad.
  2. Modify the Home URL under [User Prefs] key. (e.g Home URL="about:blank")
  3. Close notepad.


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