Volkswagen AG's US branch has indicated that over 3.3 million customers and prospective buyers were affected by a recent data breach at one of the firm's vendors. The firm says almost all of the people affected were either current or potential customers of Audi, one of VW's luxury brands. The data stolen in the breach contained sales and marketing information like phone numbers and email addresses, and was left unsecured in an electronic file by the vendor. VW has said it will offer free credit protection services to those affected by the breach.