TROJ_MSFAK.E

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.

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.