Online retailer Zappos has been a victim of a cyber attack affecting more than 24 million customer accounts in its database.

The retailer, which is owned by Amazon.com, informed its customers this weekend that some of their their names, email addresses, billing and shipping addresses, phone numbers and the last four digits of credit cards numbers and scrambled passwords were stolen. However, customers critical credit card and other payment data were intact, the retails said.

"We were recently the victim of a cyber attack by a criminal who gained access to parts of our internal network and systems through one of our servers in Kentucky," Zappos chief executive Tony Hsieh said in an email to staff which was posted on the company's blog on Sunday.

"We are cooperating with law enforcement to undergo an exhaustive investigation," he added.

Zappos is recommending that customers change their passwords including on any other website where they use the same or similar password.