Hackers keep PlayStation Network offline for fifth day

Sony says it is working to get internet-based retail service back online quickly after an 'external intrusion'

Hackers have kept Sony's lucrative PlayStation Network offline for a fifth day while engineers scramble to overhaul the system and make it more secure.

Sony's equivalent of Apple's iTunes Store, PlayStation Network is the internet-based retail service that allows users of its PlayStation 3 and PlayStation Portable devices to buy games, films, music and game add-ons, and to chat with one another.

Sony confirmed on Friday that the service had been attacked by hackers, describing it on the official PlayStation blog as an "external intrusion". Patrick Seybold, senior director of corporate communications, wrote that Sony planned "a thorough investigation … to verify the smooth and secure operation of our network services".

In an update on Monday, Seybold wrote: "This is a time intensive process and we're working to get them back online quickly."

Staff have not been given any details about the problem, which first resulted in PSN going offline last Wednesday. A weekly internal progress email mentioned the "external intrusion" but did not give any indication how long the service would remain offline.

Sony's troubles began when it removed the "Other OS" option from all PS3 consoles in March last year, which meant users could no longer choose to install and run the Linux operating system. Sony cited security concerns, but the move triggered some users to hack the PS3 so that they could still run Linux.

Sony then moved to sue a group of hackers that included 21-year-old George Hotz – who had already earned a reputation after jailbreaking the iPhone – who had allegedly published a root key for the PS3 that meant any content, such as films and music, could be played on a jailbroken device.

The high-profile Hotz case, which was settled out of court this month, attracted attention from the Anonymous hacking network, which pledged to target Sony. A post on the Anonymous blog on 4 April said the action against Hotz and fellow hacker Graf_Chokolo was "wholly unforgivable".

"You have victimised your own customers for merely possessing and sharing information … Your corrupt business practices are indicative of a corporate philosophy that would deny consumers the right to use products they have paid for, and rightfully own, in the manner of their choosing," it said.

Despite the threats, a later post on the blog stated "for once we didn't do it" and said Sony could be "taking advantage of Anonymous' previous ill-will towards the company to distract users from the fact the outage is actually an internal problem with the company's servers".

Patrick Garrett, on the games industry blog VG24/7, said the PSN crisis could have dire consequence for Sony if it did not adopt a more sophisticated strategy for dealing with hackers. "PlayStation's entire 2011 so far has been marred by a single issue: hacking," he wrote. "Sony has now allowed the issue to affect its entire audience: it has been forced to deny millions of PSN users a key PlayStation feature over a global holiday."

Garrett referred to speculation that hackers might have compromised personal information for Sony to have taken the serious step of closing PSN for five days. PSN has an estimated 75 million users worldwide, many of whom have credit card information registered with the service.

"Sony's escalation of its war on hacking could potentially threaten not only Sony's ability to cut content deals, but, in a nightmare scenario, may compromise personal information of its millions of users. Sony must demonstrate it is capable of dealing with this situation right now. If these episodes become regular in any way, PSN's users, core or not, will lose faith in its brand and gravitate elsewhere."