KuCoin suffered a September 2020 exchange breach in which attackers gained access to hot-wallet private keys and stole cryptocurrency, with reported losses ranging from at least $150 million to roughly $275-$280 million. Chainalysis attributed the hack to Lazarus Group based partly on laundering patterns, including movement through structured mixer payments, OTC brokers, exchange deposit addresses, and DeFi services such as Uniswap to swap stolen tokens without a custodial intermediary.