bitcoin has come a long way and has withstood some notable hacks. Currently, the attacks on bitcoin are more political. some of the previous attacks that are worthy of note are:
Allinvain
It’s not a bitcoin service, but honorary mention has to go to Allinvain, a member of the BitcoinTalk forums who, in June 2011, became the first person to suffer a major loss owing to a bitcoin hack.
Mt Gox
The first MtGox hack came a little after Allinvain’s. The company, which at the time had a near-monopoly on the trade between bitcoins and real money, suffered a catastrophic hack just one week later.
An attacker with a Hong Kong IP address compromised an account on the site, and then made a massive sale of bitcoins, causing the price of the currency to drop from $32.00 per coin to mere pennies. Ironically, the hackers themselves didn’t even manage to profit from it; their attempts to withdraw the looted money hit up against Mt Gox’s withdrawal limit of $1000 a day.
Bitcoin Savings and Trust
Following the collapse of the first bitcoin bubble, hacking activity died down for a bit. With bitcoins worth single-digit dollars, there was less motivation to steal them. But in the summer of 2012, one of the biggest – in bitcoin terms – scams ever began to fall apart.
These are a few of them. you can read more here: https://www.theguardian.com/technology/2014/mar/18/history-of-bitcoin-hacks-alternative-currency
PS:
I would be glad to know more from old members of the forum. History is good for posterity.