What is Spam?
Spam is unsolicited email. From the sender’s point-of-view, it’s a form of bulk mail, often to a list culled from subscribers to a discussion group or obtained by companies that specialize in creating email distribution lists. To the receiver, it usually seems like junk email. In general, it’s not considered good netiquette to send spam. It’s generally equivalent to unsolicited phone marketing calls except that the user pays for part of the message since everyone shares the cost of maintaining the Internet.
This is a defacto industry standard.

If the MailScanner application detects a virus or suspicious attachment it will replace the infected file with a “Virus Warning.txt” file to prevent the recipient’s computer from becoming infected. Both the sender and recipient are notified via email.

Opening Attachments Safely
Regard anything that meets the following criteria with particular suspicion:

Always be careful of email that has been identified as Spam by the MailScanner application. While automated Spam identification is not perfect and cannot be totally relied on to automatically Trash, it currently provides a fairly high hit rate for identification of unsolicited email.

1) If they come from someone you don’t know, who has no legitimate reason to send them to you.
2) If an attachment arrives with an empty message.
3) If there is some text in the message, but it doesn’t mention the attachment.
4) If there is a message, but it doesn’t seem to make sense.
5) If there is a message, but it seems uncharacteristic of the sender (either in its content or in the way it’s expressed).
6) If it concerns unusual material like pornographic websites, erotic pictures and so on.
7) If the message doesn’t include any personal references at all, (for instance a short message that just says something like “You must take a look at this”, or “I’m sending you this because I need your advice”).
8) If the attachment has a filename extension that indicates a program file.
9) If it has a filename with a double extension, like FILENAME.JPG.vbs or FILENAME.TXT.scr, that may be extremely suspicious. As far as Windows is concerned, it’s the last part of the name that counts, so check that to find out whether it’s a program masquerading as a data file, such as a text file or jpeg (graphics) file.

In all the above instances, it is recommended that you check with the sender that they knowingly sent the mail/attachment in question.