Bitcoin exchange Bitstamp has been a target of a hacking attack, which lead to the theft of “less than 19,000 BTC” The Slovenian-based exchange has frozen its user accounts, blocked deposits as well as other transactions and suspended the trading business. The company reassured its users that the security breach only affected its “operational wallet,” i.e. only “a small fraction of customer bitcoins” that were stored on internet-connected servers. There is no clue about the hackers and how the theft happened.
Source: https://thehackernews.com/2015/01/bitstamp-bitcoin-exchange-hacked.html