The email's headers have been spoofed to make it look like the message was sent by a printer inside the victim's enterprise, and the fact that the crooks chose the HP brand is accidental - they could have just as easily have used - and have in the past - Xerox, Lexmark or any other popular brand of printers, scanners, or photocopiers.
This type of malicious spam is constantly being recycled by cyber crooks, and I can easily see why: if you are at work, and busy doing your job, there is a high possibility that you will open the email and click on the link / download the attachment without thinking twice about it because your attention is focused on other things.
"If you work in a business environment, you might well be used to receiving dull-looking emails from printers and scanners in your workplace containing attachments of the scan that the device has just completed," points out Graham Cluley, and malicious emails such as this one simply blend in.
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