When you receive an email message with a PDF attached, it is always best to confirm that you are expecting the attachment before opening it. However, if you receive a Word, Excel, or another file type other than a pdf, beware.
In the past several days, two of our customers suffered a potential breach when their users opened Word documents sent as attachments. The infected files slipped right past sophisticated email protection systems.
Fortunately, at both companies, the IT teams got involved early on and averted disaster.
In one case, the attachment came from a trusted third party that was unaware their systems were compromised. Remember, your security is only as good as the security of your third party providers.
If you unexpectedly receive an email message with any attachments other than pdf files, be very skeptical and notify IT immediately. You may save the security of your organization.