AT&T attributed the motive of the attack to a criminal market for illegally obtained personal information. In fact, the data also included customers' credit card details.

To date, AT&T has not provided details about how the site was hacked, however some unconfirmed reports attribute the Web site as being vulnerable to Cross Site Scripting (XSS).

This attack did not come without cost to AT&T. The company notified each customer by e-mail and is now working with law enforcement officials to track down the hacker. AT&T committed to pay for credit monitoring services to protect those customers purchasing Digital Subscriber Line (DSL) equipment online from possible fraud.

Web sites with Web applications such as shopping carts, forms, login pages and dynamic content, in general, are always a prime target for attack. To function fully, Web applications require open and direct access to backend databases: if improperly coded, Web applications become easy gateways to social security numbers, credit card details, and even medical records.

Hackers experiment heavily with a wide variety of techniques to lay their hands on this type of data since the pay-offs are enormous.