Watch out for an email notifying you that you have a fax 'from' eFax, which includes an attached 'document' - it's spam and the document will contain malware.
Email subject line is 'Fax message from "unknown" - 1 page(s)'
The email shown here was first seen 23/11/15 and reads as follows:
You have received a 1 page fax at Mon, 23 Nov 2015 15:36:46 +0100 .
* The reference number for this fax is latf1_did12-13081234973-8882343633-79.
You can view your fax by opening the attached file.
Please visit [link removed] if you have any questions regarding this message or your service. You may also e-mail our corporate support department at [email address removed]
Thank you for using the eFax Corporate service!
Don't open the attached document, it's malware.