USPS E-mail Attachment is a virus.

If you get an email from what appears to be USPS with an attachment, it is most like a virus.

From: USPS client manager Terry Dunlap [mailto:reports@usps.com]
To: { your email address }
Subject: USPS delivery failure report
Attachment: USPS report id##########.zip
Notification
Our company’s courier couldn’t make the delivery of parcel.
REASON: Postal code contains an error.
LOCATION OF YOUR PARCEL: KnoxvilleFort
DELIVERY STATUS: sort order
SERVICE: One-day Shipping
NUMBER OF YOUR PARCEL: Z3UI3N0Y1Q
FEATURES: No
Label is enclosed to the letter.
Print a label and show it at your post office.
An additional information:
If the parcel isn’t received within 30 working days our company will have the right to claim compensation from you for it’s keeping in the amount of $8.26 for each day of keeping of it.
You can find the information about the procedure and conditions of parcels keeping in the nearest office.
Thank you for using our services.
USPS Global.

As far as I know USPS does not hold your package ransom either, if something is wrong they just send it back.

USPS does not send out emails like this.  If you think you have been infected, you can contact WilTech Services 940-320-9114 for assistance.