Stolen-data Trove Offers Look Inside A Botnet

Caches of stolen data like these are hidden throughout the Internet, usually locked away inside password-protected Web sites or heavily fortified servers. Prevx's researchers were able to infiltrate this site because it was protected with poor encryption.

In that sense, the find illustrates how even sloppy crooks can vacuum up enormous amounts of information through massive "botnets" — armies of infected computers formed by spreading a computer virus that orders compromised machines to phone home for further instructions, such as sending out spam or relaying passwords.

The botnet Prevx found was only harvesting data, though Prevx said it could have been upgraded to do other things.

Ordinary Internet sessions are logged in great detail. One Southern California 22-year-old could be seen registering a domain name with GoDaddy.com, changing his Yahoo e-mail password and ordering a meal online from Pizza Hut. His credit card number, birth date, telephone number, address and passwords are now all in criminals' hands, though it's unclear what, if anything, criminals have done with the information yet.

Some victims are gold mines for sensitive data. An infected computer at a Georgia bank exposed customer details and credentials for the bank's wire-transfer system. Bank employees were checking e-mail, looking up BMWs and Infinitis and working with customers' accounts on the same infected machine.