This apparently took place back in October where the hackers, calling themselves Egregor, told ZDNet, “In case Ubisoft will not contact us we will begin posting the source code of upcoming Watch Dogs and their engine.”
The group had also previously posted onto a website, which has now been taken offline, where they said, “We found source codes in free access in the main network. Passwords in the doc files without any protection, all the employees and developers data and personal information, contract, game engines and a lot of more. Guys, if the goal of the last mission in your game about hackers was the hack of your company, we’ve done it. There’s our prize?”
Ubisoft has since acknowledged that they were aware of Egregor’s alleged hack and are looking into what they are calling a “potential data security incident”, but stopped short of actually acknowledging if any files were stolen in the process.