Bitcoin7 Hack

On 2011-10-05 Bitcoin7, a young exchange that had quickly become the third-largest BTC/USD exchange behind Mt. Gox and TradeHill, said it had been hit by a series of pre-planned attacks. According to its statement, the attackers came from Russia and Eastern Europe and gained full access to the exchange's main bitcoin wallet, two of its three backup wallets, and its user database. Bitcoin7 said it would shut down and pay back lost balances over 90 days under a "crisis plan".

The amount lost is uncertain. A widely cited list of thefts puts it at 11,000 BTC. A later owners' statement, made when the exchange's code was put up for sale, implies at least 5,000 BTC, and order-book size suggests an upper bound of about 15,000 BTC. In that sale listing the owners' own account changed from an outside attack to a potential inside job, a theft by an employee. BitcoinTalk users immediately compared the case to the MyBitcoin collapse, pointing to a one-year domain registration hidden behind a privacy proxy. Bitcoin7's operators were widely suspected of an exit scam, and the "hack" has never been independently confirmed. The platform was later sold for about $10,000 in 2013 and relaunched under the Bitcoin7 brand.