The verbiage being used to describe the hack is a bit misleading. It was only a DNS hack that basically involved a social engineering exploit, that is, tricking a user into giving them the password to the dns management system and not a technical hack. They got access to DNS managment systems with Comcast's domain registrar then called someone at Comcast who dismissed their threat and then decided to redirect the dns to the site showing their shout outs.
So this wasn't a true defacement in that the actual servers weren't compromised and the actual sites were not defaced, the traffic was rerouted to a server under the hackers' control displaying their page. User data could have been compromised if they put up a similar-looking site and stole logins as people tried to access their accounts but this did not happen and they did not capture any user data.
They aren't going to get away with it because they left a trail leading right in their direction and are giving interviews and basking in their "glory".
Email:
[email protected]
Website they hastily put up for the attention:
http://www.defiants.net/
Picture they gave for their wired interview from their myspace pages:
Screenshot they gave wired of their entry to the registrar:
These idiots aren't going to be hard to find.