There's a new warning out, here is the information from Symantec.

It's called W32.Mimail.A@mm and sets itself up to appear to be a message from your system's administrator telling you that your email address is about to expire.

From Symantec:

Uses its own SMTP server to spread by email.
The email has the following characteristics:

From: admin@ (The from address may be spoofed as if to appear it is coming from the current domain)

Subject: your account %s

Message:
Hello there,
I would like to inform you about important information regarding your email address. This email address will be expiring. Please read attachment for details.

Best regards,
Administrator

Attachment: Message.zip


Message.zip contains only one file, Message.htm, which uses a code base exploit to create a copy of the worm named Foo.exe in the Temporary Internet Files folder, and then runs it. The compression method for this file inside the zip file is stored so that there is no compression used at all.

Information about this vulnerability and a Microsoft patch is located at: http://support.microsoft.com/default.aspx?scid=kb;en-us;330994
System administrators are encouraged to apply the Microsoft patch to prevent infection by this worm.

SRS