Bitcoin exchange Poloniex says, whoopsie, one of those danged software bugs resulted in 12.3% of their bitcoins being stolen. It hardly matters if Poloniex was stealing from themselves or if they are just clueless idiots. The code that runs Bitcoin exchanges can easily be hacked, gamed, and exploited. In this case, Poloniex code failed to do the simplest and most obvious of accounting tasks – checking balances before allowing withdrawals.
Poloniex owner Busoni explained that the hacker found a flaw in his site’s code that processes withdrawals. The hacker discovered that multiple simultaneous withdrawals are processed essentially at the same time and that the system’s software doesn’t check quickly enough for a negative balance, so they are still processed.
The exchange says all remaining balances will get a “temporary” 12.3% reduction. No word yet on why the reduction will be temporary or if they’ve fixed a software flaw that never should have been there in the first place.