Of the two gaming networks, Sony's PSN appears to have been the hardest hit. It took three days before PSN finally came back up. Microsoft's Xbox Live came up faster but for two days it reported that while its core services were up and running, its Xbox Live service was "limited."
DownDetector, a service that tracks user twitter reports of Internet site and service outrages, reported that many gamers were having trouble playing on PSN and Xbox Live from Christmas Day until Sunday. Both Microsoft and Sony actively repaired their services, but they were unable to fight off their attackers for days.
These attacks were caused by Distributed Denial of Service (DDoS) assaults. These attacks were coming, according to data from Arbor Network and Google's Digital Attack Map and Internet security company Norse's IPViking, from sites around the world and using a wide variety of DDoS techniques. These included overwhelming the gaming networks by sheer volume and TCP/IP fragmentation.
Taking credit for this, if credit is the right word, is a hacker group that calls itself the Lizard Squad. This group is best known for attacking gaming networks. In the past few months, the organization has claimed to have shut down PSN, Blizzard's Battle.net, and other gaming networks.
In an "interview" on WinBeta Lizard Squad claimed that they started attacking sites for fun. But now they're doing it to force Microsoft and Sony to improve their security. They chose to make their major attack on Christmas to annoy the largest number possible of users to further this goal.
In an odd twist, Kim Dotcom, who's still fighting a legal battle with New Zealand and the United States over charges of enabling online file privacy, offered Lizard Squad free storage on his Mega cloud storage system if they ceased attacking. While Dotcom claims that Lizard Squad has accepted the deal and that Xbox Live and PSN services were being restored because of it, both networks had serious problems or were down entirely for approximately 48 more hours.