TROJ_MSFAK.E

October 09, 2012
 Analysis by: Michael Cabel
 Modified by: Kathleen Notario
 ALIASES:

Trojan:Win32/Comitsproc (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

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:

36,974 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Feb 2012

Payload:

Downloads files

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 copies of itself into the affected system:

  • %User Startup%\IEXPLORE.EXE

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Autostart Technique

This Trojan modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "{Malware Path and File Name}"

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

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://www1.{BLOCKED}m.onedumb.com/apc.gif

It saves the files it downloads using the following names:

  • %User Temp%\IEXPLORE.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.)

NOTES:

As of this writing, the URL where the file can be downloaded is already inaccessible and it redirects to http://www.yahoo.co.jp. As a result, the downloaded file saved as %User Temp%\IEXPLORE.EXE is a non-malicious HTML file.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.806.04

FIRST VSAPI PATTERN DATE:

28 Feb 2012

VSAPI OPR PATTERN File:

8.807.00

VSAPI OPR PATTERN Date:

29 Feb 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

Identify and delete files detected as TROJ_MSFAK.E using the Recovery Console

[ Learn More ]

Step 3

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\Windows NT\CurrentVersion\Windows
    • From: load = "{Malware Path and File Name}"
      To: load = ""

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 Temp%\IEXPLORE.EXE

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_MSFAK.E. 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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