The PSN was comprised of multiple forwarding servers. This server had no encryption, no DDoS protection was in place. Key players in PH4N70M include an exploiter (TH0R), Xik, and several others including the operation payback collaborator named Wolfy. The credit card concerns were all because the data was never encrypted when sent. The original planned attack was going to be a LOIC + Slowloris attack. I also heard before I left of a bufferoverflow attack.
Source: https://thehackernews.com/2011/05/role-of-hacking-in-stealing-and-selling.html