Steam forums are currently down, security breach is to blame?

Steam's official forums are currently offline with a message reading "The Steam forums are temporarily offline for maintenance. Your patience is appreciated." Is maintenance the actual issue, though? It is believed that the site's vBulletin forum software may have been hacked, with Valve not yet to comment on the issue, with some gamers noticing a suspicious message on the forum last night that leads most to believe it was a security breach.

Eurogamer was contacted by a Steam user who said a group known as fkn0wned changed the text on the forum and spammed some user's e-mail addresses. Below is what was said:

Ever wanted to dominate the servers you play on with guaranteed results, but you were too afraid to cheat because of ban risks? Visit Fkn0wned.com. It's safe, secure and undetected. Along with hacks, we've also got some general discussion sections, hacking tutorials and tools, porn, free giveaways and much more. This site has been conditioned to meet all of your needs in terms of resources so be sure to take a look and tell us what you think. Thanks again, the fkn0wned team.

RIght now, no one knows if private data such as passwords and billing information has been stolen, with the breach taking place sometime last night. More information should hopefully be made available soon, or the forums might just appear to be working shortly.