Kraken's user database has been hacked.
Many accounts have been robbed.
Kraken are trying to blame their customers for the fact that they have been robbed (cos that way Kraken reckon they are not liable to refund their customers), but owing to the sheer volume of simultaneous incidences of accounts being comrpomised, it is obvious that the security problems lie with them.
From my own correspondence with Kraken support, I have gotten no useful or helpful information out of them other than that they are 'sorry for your loss'. From correspondence that I have seen from other people whose Kraken accounts were emptied, I have seen Kraken support try to insinuate that hackers have compromised the user database of Bitfinex, and are using the username and password info to empty Kraken accounts.....but not to empty Bitfinex accounts, oddly enough....perhaps because Bitfinex operate Email verification as a mininum security requirement, whilst Kraken do not......
....but no....
...in reality, Kraken are having security problems, with the rat(s) most likely operating from within, lots of funds are being stolen, and Kraken's only concern regarding their customers is to cover their own backs and deny any culpability......if u have any choice in the mater regarding your MtGox funds, steer well clear of!