I'm sure you've all had them, attachments appearing in your email inbox from various companies, some familiar and some not, which claim to be invoices or order details. They are malicious attachments, some are zip files or pdfs, or other less familiar file types, but they are all attempting to attack your computer through its weakest link. That link is between your chair and your keyboard. Yes that's you! While spam filters do a pretty good job on the whole of stopping such junk from hitting your inbox invariably some of it is going to get through.
You are the last defence in stopping these files doing damage to your computer. While they may appear to do nothing harmful they are most likely compromising your computer, allowing information to be stolen, or enlisting your computer into a bot-net, which can then be used to attack others.
These fake emails are usually pretty easy to spot. You will usually get several of them rather than just one, and most likely each one you receive will have a different numerical reference number in the subject field. The correct response is to delete the email without opening the attachment. If you think you have done something silly, like open the attachment, even if it appeared to do nothing, make sure your virus checker is completely up to date and do a full virus scan. If you are in a company then report it to your IT administrator.
So remember if you don't remember ordering something from a company you most likely didn't. If you are not sure go directly to the company's web site through your browser and check your account or order list. Always enter the web site address directly into your browser yourself. Malicious links can take you to fake web sites which might well look exactly like you would expect but in fact are run by criminals.