A statement from the Hard Rock Hotel & Casino, linked from their home page:
The trust and loyalty of our customers is our highest priority, which is why, as a precautionary measure, we are writing to let you know of a security incident that may have affected your credit card information.
This incident may have allowed criminal hackers access to information about credit or debit cards used at certain Hard Rock Hotel & Casino Las Vegas retail and service locations. The information potentially affected includes names, card numbers, and CVV codes, but does not include PIN numbers or other sensitive customer information.
This criminal attack was limited to credit or debit card transactions between September 3rd, 2014 and April 2nd, 2015 at restaurant, bar and retail locations at the Hard Rock Hotel Las Vegas property, including the Culinary Dropout Restaurant. The attack did not affect transactions at the hotel, casino, Nobu, Affliction, John Varvatos, Rocks, Hart & Huntington Tattoo or Reliquary Spa & Salon.