F-Secure Virus Descriptions : Redlof

NAME:	Redlof
ALIAS:	VBS.Redlof, VBS/Redlof
ALIAS:	VBS/Redolf

Redlof is polymorphic virus that embeds itself without any attachment to every e-mail sent from the infected system. It executes when an infected email message is viewed.

VARIANT: Redlof.A

VARIANT: VBS/Redolf.A

VBS/Redlof.A@m executes directly from an infected message by using a security vulnerbility in Internet Exlorer known as Microsoft VM ActiveX Control Vulnerability. More information about the vulnerability and a fix is available from Microsoft: http://www.microsoft.com/technet/security/bulletin/ms00-075.asp

When the virus executes, it infects a file "web\Folders.htt" at the Windows installation directory which causes that the virus activates when any directory is opened using the Active Desktop's web folder feature.

The virus also infects files with extensions "htm", "html", "asp", "php", "jsp", "htt" or "vbs".

Redlof drops the following infected files:

    \Program Files\Common Files\Microsoft Shared\Stationery\blank.html
    \Windows\System\Kernel32.dll
    \Windows\web\kjwall.gif
    \Windows\system32\desktop.ini

"blank.html" is used to replace the default stationaries for both Outlook and Outlook Express via registry causing that the every message sent from an infected system will carry the virus.

The "Kernel32.dll" is also set to registry so that it will be executed on the system restart:

    HKLM\Software\Microsoft\Windows\CurrentVersion\Run\Kernel32

[Analysis: Sami Rautiainen, F-Secure Corp.; July 16th, 2002]