It's not all too often that an MMO developer is forced to issue a warning about hacked accounts - much less take certain services offline as a result - so if you play World of Warcraft, take note. Blizzard yesterday posted a statement to its Battle.net site stating that there's been an increase in unauthorized account login attempts via the official website and also the mobile armory app.
According to WoW Insider, the issue lays entirely with the armory app, where compromised accounts are used to spend obscene amounts of gold on ridiculously-priced white items (in effect, transferring the gold without actually logging into the game client).
As a result, Blizzard has gone ahead and disabled the auction house on most (or all, it's not clear) shards, and the armory app is effectively useless for the time-being. If your account is one that's been compromised, you can expect to receive an email from Blizzard about it soon - but please, if you do, make absolute sure that it's an official Blizzard email and not a phishing attempt. Events like these are like a goldmine for those trying to gain unauthorized access to your account.
While full server rollbacks for events like these are impossible given the amount of time that's passed, Blizzard has stated that upon request, customer service will be able to restore the in-game items and gold that were effectively stolen from you. I must give Blizzard major kudos there, because that wouldn't be the case with most MMOs.