Ubisoft, one of the world’s largest games developers, says it’s working to fix an apparent hack on popular online shooter Rainbow Six Siege.

Servers for the tactical multiplayer game were taken offline on Saturday and Sunday after in-game currency thought to be worth millions of pounds was distributed to players.

The company has since restored service, but suspended the game’s marketplace until further notice and warned players they may face queues when trying to log on.

In a statement on X, Ubisoft said it would continue to make “investigations and corrections” over the next two weeks.

Rainbow Six Siege, commonly referred to as R6, has been a success story for Ubisoft, which is also behind the Assassin’s Creed and Far Cry series.

The game has a steady base of regular players and its own dedicated esports tournaments.

It’s currently free to play, but generates income for the company through in-game purchases of cosmetic items via its online marketplace.

Ubisoft has not officially described the weekend’s incident as a hack, but did acknowledge issues that affected the game over the weekend.

According to reports, R6 players were each sent 2 billion credits – estimated to be worth $13.3m (£9.9m) if they’d been bought legitimately.

Screenshots also showed messages containing defamatory statements appearing for some users.

In response, Ubisoft shut down its R6 servers and began to work on a “roll back” – essentially rewinding the clock so any purchases made prior to Saturday could be undone.

The company said any irregular messages were not sent by its team members, and added that no-one would be banned for spending credits they had received.

Journalist James Lucas, who has been covering the story for website The Gamer, says it’s unusual to see an attack on this scale on such a high-profile title.

“You could empty the store a dozen times over,” says James.

James adds that the timing of the outage, during the lucrative Christmas period, comes at a particularly bad time for Ubisoft.

“We talk about Christmas noobs, people who get the game for the first time over the holidays,” says James.

“The marketplace is disabled, so there’s no way to buy in-game items any more.

“All of that money is sitting on the table now because they can’t spend anything on the game.”

Long-term players are also affected, says James, with some still missing purchased items.

“I think it shows a really big vulnerability,” says James.

“If a hacker can gain access to your backends, even with a backup, your game or at least your marketplace could go offline for weeks.”

James added that reports of a wider attack, with hackers gaining access to data linked to unreleased Ubisoft games, appeared to be untrue.

Gaming hacks are relatively rare but there have been some high-profile examples.

One of the biggest was in 2011, when PlayStation Network was taken offline for 24 days.

About 70 million accounts were compromised, and UK regulators fined Sony £250,000 with UK authorities saying it “could have been prevented”.

Developer Rockstar was among a series of major companies targeted in a series of hacks in 2021 and 2022.

Early footage of its upcoming Grand Theft Auto 6 was leaked, and a teenager was eventually sentenced in a UK court over the attack.

And Ubisoft itself was the victim of a 2013 hack that resulted in user account data being stolen.

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