Sony PlayStation mostly back online

Sony’s PlayStation Network is slowly coming back online after four days of outages due to a Christmas Day cyberattack, Sony said late Sunday.

A hacker activist group that goes by Lizard Squad has claimed responsibility for the attack, which also took down Microsoft’s Xbox Live system for two days, starting Dec. 25. It’s the same group that took credit for cyber assaults on the PlayStation Network in early December and August of this year, and as far back as 2011.

{mosads}Sony said Saturday that the system was back online but “from time to time there may be disruptions in service due to large surges in traffic.”

PlayStation Network and Xbox Live were initially taken offline by what’s known as a denial of service attack, where hackers artificially flood a network with traffic, causing it to overload and crash.

Those disruptions were still occurring Sunday, according to Sony’s official customer support Twitter account. But for the most part, service was back up.

“If you are still having issues signing in to [PlayStation Network] today, please reboot the console and try again,” the account tweeted late Sunday.

It’s bad timing for Sony, which is still reeling from the devastating cyberattack on Sony Pictures that caused the studio to almost cancel and ultimately limit the release of its controversial comedy, “The Interview,” which depicts the assassination of North Korean leader Kim Jong Un.

The studio has also had troves of internal documents leaked, causing embarrassment to top executives and millions in cleanup costs.

Cybersecurity firm IntelCrawler believes Lizard Squad may have connections to the hacking group behind the Sony attack, Guardians of Peace. The FBI has blamed North Korea for sponsoring the hit, but some security experts remain skeptical of that conclusion.