They DDoS’ed all manner of government and financial sites, including NASDAQ, ca.gov, and CIA.gov, which they took down for a matter of hours in April. They bypassed Google two step, hijacked 4chan’s DNS and redirected it to their own Twitter feed, and repeatedly posted Mayor Michael Bloomberg’s address and Social Security number online. After breaking into one billing agency using social-engineering techniques this past May, they proceeded to dump some 500,000 credit card numbers online. Cosmo was the social engineer for the crew, a specialist in talking his way past security barriers.
Cosmo, who is currently being held in a juvenile detention center, explains that many of these attacks he’s taken part in aren’t all that difficult—in many cases all he needed was a few pieces of information like the last four digits of a social security number and an email address.
More:
http://gizmodo.com/5942330/a-hacker-who-isnt-old-enough-to-drive-but-can-destroy-your-digital-life