One of the key selling points for cryptocurrencies is that they are secure and cannot be hacked. Through blockchain, a cryptocurrency network automatically checks itself for authenticity, thereby eliminating a direct attack on the network itself. However, the cryptocurrency exchanges, individuals and companies working with the technology are still vulnerable. Hackers know this, and they have initiated several cryptocurrency hacks over the years. The largest of them have managed to create a blotch on the network, such as these.
Mt. Gox hack
This is the most often quoted case among cryptocurrency hacks. By 2013, Japan’s Mt. Gox was the world’s largest cryptocurrency exchange, holding a large portion of bitcoin volume itself. In 2014, though, the exchange filed for bankruptcy after the company discovered it had lost about 850,000 bitcoins worth $473 million at the time. These were also about 7% of the entire number of bitcoins in circulation. After investigations, it was discovered that the theft had occurred over several years since 2011 with hackers siphoning bitcoins bit by bit. A few of the bitcoins have been recovered, and several clients refunded, but the majority of bitcoins were lost permanently.
When Ethereum had proposed the use of DAO tokens as a form of crowdfunding in April last year, the ICO became instantly popular. In under 3 weeks, the ICO had raised over $150 million, making it one of the best ICOs even by today’s standard. Soon thereafter, hacker(s) found a vulnerability that enabled them to take off with $50 million worth of ether tokens. Among cryptocurrency hacks, this was significant enough to even force Ethereum to perform a hard fork into Ethereum and Ethereum classic. Nevertheless, they were still not able to recover the stolen tokens, even though their value was diminished after the attack.
Soon after the DAO attack, in August of 2016, hackers gained access to Bitfinex exchange and through a vulnerability in its MultiSig wallets, managed to steal $72 million worth of bitcoin.
Parity Technologies hack
This year in July, hackers found a bug in wallets provided by parity technologies. Upon exploiting the bug, they managed to freeze 513,774.16 ether tokens in users’ wallets. Based on the value of ether tokens at the time, the hackers had frozen about $245 million worth of tokens. The event echoed some of the previous cryptocurrency hacks, and there were even fears etherem would have to hard fork again. However, some white hat hackers also used the bug to drain the funds safely and recover clients’ funds. In the end, the hackers had still made away with $32 million in ether.
Most recent is an attack on the company Tether, where the hackers got away with $30.9 million in tokens. The detains of this hack are still being unravelled, but Tether is still assuring its clients that they are working on a way to recover the stolen tokens.