Threat Description

CoolNot

Details

Aliases: CoolNot
Category: Malware
Type: Worm
Platform: VBS

Summary



VBS/CoolNot is a worm, similar to the VBS/LoveLetter.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details




Variant:CoolNot.A

VBS/CoolNot.A uses Outlook to sent itself to all recipients in every address book. The message that it sends is as follows:

 Subject:    Cool Notepad Demo
    Body:       Hey check out this text file I sent it will do
    something neat in notepad.
    Enjoy :-)
    Attachment: COOL_NOTEPAD_DEMO.TXT.vbs

It copies itself to the Windows System directory as "COOL_NOTEPAD_DEMO.TXT.vbs" and adds a key to the registry so that it will be executed next time the system is restarted.

Then the worm replaces the "script.ini" file from the mIRC installation directory. The worm uses this modification to send itself to those users who join to the same channel as the infected user. In addition, the worm will join to the "#virus" channel and send a message "Cool Notepad Demo" to that channel.

As a payload, the worm adds a registry key that will hide the desktop after the system is restarted. This registry key is:

 HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDesktop

To restore your desktop, please download and execute the following registry file: ftp://ftp.F-Secure.com/anti-virus/tools/coolnote.reg





Description Created: Analysis: Katrin Tocheva and Sami Rautiainen, F-Secure


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