This is a worm which attempts to use Microsoft Word 97 to send email to everyone at the address book of the current user. However, it will no infect any Word documents and will work only if the installed email client supports MAPI (Mail API, supported by most modern Windows email programs).
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
W97M/Nail will start a new MAPI session and logon as the current user. It will use a random number to select the message out of four different possibilities:
1. Subject: Good TimesText: New information on this apparent hoax.. 2. Subject: New DevelopmentsText: I thought you should know about this recent development... 3. Subject: WWIII!Text: Check out CNN.Com or read this 4. Subject: Market share tipoff...Text: Please don't share this information with anyone
Next, it will add the name of the user to the end of the message. After that, the worm will add the message to the outbox and collect every address from the user's address book. The worm will add all collected addresses to the receiver of the message and attachs itself (ActiveDocument) to the message. This way the users who receive the attachment and open it with Microsoft Word 97 will spread the worm to the users from their address book.
The worm will also create another message from the collected address book and a random message from user's inbox. This message will be sent to an email address (chainnail@hotmail.com) which probably belongs to the virus writer.
Finally it will send both messages and close the MAPI session.
The virus code contains this comment:
Automated Chain Mail v0.1