Group-IB has estimated that crypto exchanges suffered a total loss of $882 million due to targeted attacks between 2017 and 2018. Five attacks have been linked to North Korean hackers from Lazarus state-sponsored group, including the infamous attack on Japanese crypto exchange Coincheck, when $534million in crypto was stolen. In 2017 more than 10% of funds raised through ICOs were stolen, while 80% of projects disappeared with the money without fulfilling any obligations towards their investors. In H1 of 2018 alone, ICO projects raised almost $14 billion – twice as much as during the entire 2017 ($5,5 billion)”]
Source: https://securityaffairs.co/wordpress/77213/hacking/cyber-attacks-crypto-exchanges.html