Zappos breach goes beyond credit cards: Consumers face identity theft if hackers correlate other penetrated databases

Wicker conducts research in wireless information networks. He focuses on networking technology, law, and sociology, and how regulation can affect the privacy and speech rights. He is the author of the book "Cellular Convergence and the Death of Privacy," to be published by Oxford University Press at the end of 2012.

He says: "Though Zappos has not stated how security was breached, this event is a reminder that security is not a fix or an overlay, it is an ongoing process that must be intrinsic to the design and maintenance of an Internet presence.

"Zappos said that credit card information was not stolen, but acknowledged that email addresses, billing and shipping addresses, phone numbers, and the last four digits from credit cards may have been compromised. This is a lopsided outcome for the customer.

"The bigger problem Zappos faces is that large databases of consumer information can be used for identity theft. As Zappos acknowledged, users who use the same or similar passwords are at risk of theft through access to other sites such as Amazon or Ebay.

"More generally, information about a customer can be used to 'de-anonymize' other databases on other Web sites, further invading customer privacy. Correlation attacks enabled by such data have been shown to strip anonymity from NetFlix, AOL and other databases that were assumed safe. Thus, the information used can include customer preferences, beliefs and practices that are far harder to change than a credit card number.

"Zappos' response is admirable for its forthrightness and immediacy, but this is a reminder of the risk run when online service providers maintain databases of user data. This is a practice that many, many web site and service providers engage in for convenience and, in some cases, for profit. This is a practice that a networked society cannot afford for the long term if individual privacy is to be preserved."