Be wary of unsolicited attachments, even from people you know - Just because an email message looks like it came from a familiar source, malicious parties often "spoof" the return address, making it look like the message came from someone else. If you can, check with the person who supposedly sent the message to make sure it's legitimate before opening any attachments. This also includes email messages that appear to be from your Internet Service Provider (ETC) or software vendor claiming to include patches or anti-virus software. ISPs and software vendors do not send patches or software in email.