Ubisoft's controversial DRM servers were attacked and brought down over the weekend, preventing some Assassin’s Creed II and Silent Hunter 5 owners in Europe from playing their PC games. The publisher's new online authentication policy seeks to prevent pirates from playing its PC releases by requiring users to stay connected to its DRM servers while playing its games. Assassin’s Creed II, Silent Hunter 5 and The Settlers 7 are the first titles from the company to implement this technology. Many critics of the policy worried they would be unable to play their legally owned copies of Ubisoft's titles should its DRM servers go down, which was the case for some European gamers over the weekend when the DRM servers were inaccessible to a portion of players who wanted to run Assassin’s Creed II and Silent Hunter 5. An online community manager for the company explained, "Due to exceptional demand, we are currently experiencing difficulties with the Online Service Platform. This does not affect customers who are currently playing, but customers attempting to start a game may experience difficulty in accessing our servers. We are currently working to resolve this issue and apologize for any inconvenience." Ubisoft then clarified this morning that its limited service was due to its servers coming under attack. "95 percent of players were not affected, but a small group of players attempting to open a game session did receive denial of service errors," said the publisher in its official Twitter account. The server attack and crash follows several days after reports circulated that hackers circumvented the newly introduced DRM technology. The company later issued a statement denying that its games using the online authentication platform had been cracked and claiming that hacked versions of Assassin’s Creed II and Silent Hunter 5 are incomplete.