Newslink: Half Billion Dollar Hack of Crypto Exchange Now Thought Work of Russians
TL;DR: Japanese cryptocurrency exchange Coincheck was hacked in early 2018 for more than $500 million. Accounts at the time and since have placed the blame on black hats from North Korea. Recently, however, local media in Japan uncovered what they believe is enough evidence to suggest perhaps Russians were the main culprits.
https://coinspice.io/news/half-billion-dollar-hack-of-crypto-exchange-now-thought-work-of-russians/
All the experts have been warning about leaving cryptos on exchanges and many people just don't seem to bother to heed to their advice.