Summary

When the worm is executed, it first copies itself to Windows directory as "THE_FLY.CHM" and to Windows system directory as "DXGFXB3D.DLL".

Next t opens a window with a picture and the following message:

    If you ride a motorcycle, close your mouth.

After the window has been shown the worm drops an JavaScript file, "MSJSVM.JS", to the Windows system directory. The it modifies the Windows registry in a such way that this script will be executed on each system startup.

Then JS/The_Fly will use Outlook to mass-mail itself to all recipients in all address books. The message it sends looks as follows:

    Subject:    Funny thing
    Body:       > If you ride a motorcycle, close your mounth. :)
    Attachment: THE_FLY.CHM

This worm removes sent mail from the user's "Sent items" folder to hide itself.

When the system is restarted, the "MSJSVM.JS" script executes. This script will alter mIRC and Pirch98 IRC clients settings in a such way, that the worm will be sent each time when the user joins a IRC chat channel. It replaces the "script.ini" from the mIRC installation directory and "events.ini" from Pirch98 installation directory.

Finally, the number of minutes is equal to 30, JS/The_Fly shows a message box with the following text:

    //MIRC/OUTLOOK/PIRCH.CommonSense by Zulu
    if (CommonSense == true) {
      God = false;
      Religion = false;
    }
    else {
      God = true;
      Religion = true;
    }

VARIANT:

The_Fly.B

This variant is the same as The_Fly.A, except the virus code has been encrypted.

[Analysis: Katrin Tocheva and Sami Rautiainen, F-Secure]