Yet another problem with Bitcoin hacking at an exchange. Charlie Osborne on the how:
Poloniex, a Bitcoin trading post similar to Mt. Gox, has lost 12.3 percent of the Bitcoin stored in hot wallets on the website.
A hacker took advantage of a processing flaw in the Bitcoin exchange post. When users submit a withdrawal request, the input is checked against your balance, deducted, and the new amount recorded within a database. However, it was discovered that placing several withdrawals all in practically the same instant meant each request was processed at more-or-less the same time, resulting in a negative balance but “valid insertions into the database, which then get picked up by the withdrawal daemon.”
According to the Poloniex chief, auditing and security features were not explicitly looking for negative balances, and so the transactions were allowed to proceed.
Are we watching the death of digital cryptocurrency?