"The networks were taken offline due to a distributed denial of service attack," PlayStation spokesperson Sid Shuman writes in a blog post. "We have seen no evidence of any intrusion to the network and no evidence of any unauthorized access to users’ personal information."
The cyberattack coincided with a perceived bomb threat on an American Airlines flight that was transporting top Sony executive John Smedley, the president of Sony Online Entertainment. That threat is currently being investigated by the Federal Bureau of Investigation.
The plane, with 179 passengers and six crew members, was flying on Aug. 24 from Dallas to San Diego but was diverted to Phoenix before continuing on to San Diego for what the FBI called a security threat.
"Sony, yet another large company, but they aren't spending the waves of cash they obtain on their customers' (PlayStation Network) service. End the greed," one tweet read.
Throughout the crisis, Mr. Smedley tweeted information about the state of the PlayStation Network.
In addition to claiming responsibility for the attack, Lizard Squad openly compared itself to the Islamic extremist group ISIS, which also goes by the moniker the Islamic State or IS. That group recently executed American journalist James Foley in a grisly video that was circulated online.
"Today we planted the ISIS flag on @Sony's servers #ISIS #jihad," another tweet read.
Lizard Squad also took credit for targeting the servers of Blizzard Entertainment, the video game developer that makes World of Warcraft, whose website was down, Reuters reports, adding that it had also threatened to attack Microsoft’s Xbox Live network.
This comes at a time when social media sites such as Twitter and Facebook and video-sharing site YouTube have been banning content and images from militant groups. Examples include removing material from the Palestinian militant group Hamas as well as IS.
In addition, Twitter said it was suspending any accounts that posted the video of Mr. Foley's beheading. Neither Twitter nor Facebook allow groups officially classified by the US government as terrorist organizations to use their services.
In the wake of removal from traditional social media, the group IS has turned to the lesser-known, more diffuse social network Diaspora. Because it has no centralized server, it is very difficult to moderate content that gets posted to the many individual Diaspora servers, each of which is responsible for moderating its own content.
According to Twitter's rules, it "does not screen content and does not remove potentially offensive content." However, its stated rules do not allow for the posting of threats of violence against others.
And yet, it is not clear whether claiming credit for a cyberattack, as in the case with Lizard Squad, meets Twitter's criteria for being suspended from its service.
Twitter spokesperson Nu Wexler declined to comment on why that account was still up and running, noting that "We don't comment on individual accounts, for privacy and security reasons." Lizard Squad's account has more than 36,000 followers.
-Material from The Associated Press and Reuters was used in this report.