Analysis by: Marfel Tiamzon
ALIASES:

Symantec: Downloader.MisleadApp; Microsoft : Program:Win32/Winfixer

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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: 1,041,672 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 07 Jan 2011

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:

  • %User Temp%\ProductPath

(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.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SBI = {malware path and file name}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\VirusSeigyoDownloader

HKEY_LOCAL_MACHINE\SOFTWARE\VirusSeigyoDownloader

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Epoch
Epoch = 16

(Note: The default value data of the said registry entry is e.)

It also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\VirusSeigyoDownloader
TotalSize = 4cc

HKEY_LOCAL_MACHINE\SOFTWARE\VirusSeigyoDownloader
SeekPos = 4cc

HKEY_LOCAL_MACHINE\SOFTWARE\VirusSeigyoDownloader
EulaShowed = 1

HKEY_CURRENT_USER\Software\VirusSeigyoDownloader
TotalSize = 4cc

HKEY_CURRENT_USER\Software\VirusSeigyoDownloader
SeekPos = 4cc

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 5.272.09
FIRST VSAPI PATTERN DATE: 13 May 2008

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 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\Windows\CurrentVersion\Run
    • SBI = {malware path and file name}

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\
    • VirusSeigyoDownloader
  • In HKEY_CURRENT_USER\Software\
    • VirusSeigyoDownloader

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Epoch
    • From: Epoch = 16
      To: e

Step 5

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.
  • %User Temp%\ProductPath

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.Q. 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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