You get an e-mail from a big chain store that you purchase groceries from, on regular basis (eg. Walmart, Superstore, etc). “We are now happy to offer online your last receipt. Please find it attached to this e-mail.

Thank you for shopping with us”. Most likely, the attachment will be a Zip. file, that will contain a virus, keystroke logger, or malware. Look at the domain name of the sender’s e-mail. Is it the store’s name.com or does it have extra letters and numbers (bestbuy.com or bestbuy529a5.com)?

How to avoid: never open attachments from unknown senders.