What are the most notable cases of coins or wallet thefts?

In order of date:

13th June 2011, 25,000 BTC stolen from an early adopter "allinvain": A single user claims they were hacked and lost an enormous quantity of Bitcoins.
15th June 2011, 650 (?) BTC stolen from MtGox exchange: This attack probably made the news more than any other because the apparent market price plunged to $0.01/BTC, but withdrawal limits actually prevented a major loss. There was however substantial downtime and confusion amongst users while security issues were resolved. MtGox remains the largest exchange despite the issues, as at the time of writing.
31st July 2011, 27,000 BTC stolen from mybitcoin.com: This was a website that worked like an online wallet. After the website disappeared for several days, the owner reappeared claiming the site was hacked and is closing the site down, with a plan to refund 49% of each user's previous balance. There has been speculation that the owner of the site scammed the users.
1st August 2011, 17,000 BTC lost from Bitomat exchange: A surprisingly large Polish exchange was mistakenly (due to a technical misunderstanding) set up in an unstable hosting environment and lost its wallet file when the server crashed. The MtGox exchange took over Bitomat's business with an agreement to try to restore users Bitcoins.
1st March, 2012: More than 43,000 BTC were stolen from bitcoinica.com due to a Linode exploit, and another 3,000 from an individual programmer. The same exploit was used against Slush's Pool to steal 3094 BTC.
11th May, 2012: 18,547 BTC were stolen from bitcoinica.com.

I'm not aware of anyone being caught for any of these thefts.

Highly Irregular

Posted 2012-05-11T23:07:59.803

Reputation: 10 514

Hmm, haven't there been 25,000 Bitcoins stolen from MtGox right before the big hack and sale? http://www.dailytech.com/Inside+the+MegaHack+of+Bitcoin+the+Full+Story/article21942.htm

– ThePiachu – 2012-05-24T14:53:53.067

Not in my understanding. I believe 25,000 of MtGox bitcoin credits were transferred from other accounts to the hacker's account, but I believe only a handful were able to be withdrawn ($1,000 worth, probably 30-40 given the exchange rate at the time). Perhaps the hacker put the remainder up for sale at $0.01 in frustration, as most were put up for sale on MtGox? (the trades of the stolen credits were subsequently not treated as legitimate by MtGox) http://www.ugbit.com/forums/bitcoin-news-2/why-did-price-bitcoins-drop-drastically-%5Bmtgox-hacked-user-info-released%5D-6/

– Highly Irregular – 2012-05-24T19:03:50.117

bitcoinica got hacked twice? – Pacerier – 2012-06-21T14:30:13.687

@Pacerier, yes. The Linode issue was a problem with the hosting system though, rather than a security hole in the website coding. I'm not sure, from memory, what the technique used for 2nd theft was though. – Highly Irregular – 2012-06-21T19:00:01.370

@Highly Are you aware if the customers were fully refunded for both cases? – Pacerier – 2012-06-22T05:30:42.703

@Pacerier, I believe so. They have a process for providing refunds, and seem to have stated they are intending to provide a full refund. See here for more info: http://bitcoin.stackexchange.com/questions/3725/is-bitcoinica-com-planning-to-reopen-after-the-11th-may-2012-theft

– Highly Irregular – 2012-06-22T06:11:20.907

mybitcoin actually lost about 75k coins, iirc. their 'final balance sheet': https://bitcointalk.org/index.php?topic=35474.0

– nanotube – 2012-08-03T16:31:59.517

and don't forget also the 40kusd + 40kbtc stolen from bitcoinica most recently in an mtgox-account hack. – nanotube – 2012-08-03T16:33:49.797

What are the most notable cases of coins or wallet thefts?

Answers