Xbox, PlayStation Networks Attacked as Hackers Claim Credit

Microsoft Corp.’s Xbox Live and Sony Corp.’s PlayStation Network, Internet services that video gamers use to play online, were hit by connection failures on Christmas Day, with the hackers Lizard Squad claiming responsibility.

The group, which took credit for an attack on Sony earlier this year, said on its Twitter account that it was behind the incidents. The group said it would “stop hitting” the services if users called attention to the hack by retweeting its statements.

The latest incident is an annoyance for Sony compared with the attack on its TV and film unit last month. A different group called Guardians of Peace claimed responsibility for hacking into Sony Pictures Entertainment servers, destroying data, exposing Hollywood secrets, and forcing the movie studio to cancel the nationwide theater release of “The Interview.” Both groups had threatened further disruptions on Christmas Day.

“It’s not yet clear whether it’s just an outage of the PlayStation Network or if some personal data has been stolen too,” said Hideki Yasuda, a Tokyo-based analyst at Ace Research Institute. “From investors’ point of view, a data leak won’t bankrupt the company.”

Sony shares fell 0.7 percent to 2,539 yen as of the 11:30 a.m. trading break in Tokyo, compared with a 0.1 percent advance in Japan’s benchmark Topix index.

Users can now play games and download music and videos from Xbox Live, after earlier having difficulty signing into their online accounts, according to the service’s website as of 6:45 p.m. U.S. West Coast time. Users of the PlayStation Network, used to connect Sony’s gaming consoles, were still having trouble logging in, according to its support website.

“PSN was difficult to sign in from yesterday morning Tokyo time, and it recovered once in the afternoon, but currently it is in an unstable status again,” Satoshi Nakajima, a spokesman for Sony’s games unit, said by phone. “Whether this is related to the Sony Pictures Entertainment hack is still under investigation.”

E-mail and voice-mail messages to David Dennis, a spokesman for Redmond, Washington-based Microsoft, weren’t immediately returned.

Last week, U.S. President Barack Obama blamed North Korea for orchestrating the attacks against Sony Pictures and vowed to respond. North Korea has said it doesn’t know the identity of the hackers claiming responsibility for breaking into Sony’s computer network. The country’s connection to the Internet was also disrupted earlier this week.

By streaming the comedy via the Web, Microsoft and Sony took the risk of provoking denial-of-service hacking attacks. The hackers had warned that they intended to target the companies with such incidents on Christmas Day.

Denial-of-service assaults can be difficult to deflect, even if a company has ample warning they are coming, because they are executed by thousands of hacked computers performing normal but database-intensive activities, such as performing searches or downloading videos, all at the same time.

Cybercriminals targeted Sony in 2011 after it sued a young researcher when he exposed security vulnerabilities in the PlayStation 3 console. The 2011 hack involved the theft of personal data on 77 million PSN users.

“Last time the network was down for a month and PS4 sales were little affected,” Ace Research’s Yasuda said. “A network outage won’t prevent people from buying the PS4. And this time it comes after the peak shopping season, too.”