Coinbase touts 99% cold storage as Binance Breach puts crypto exchange security under scrutiny

Coinbase said it keeps more than 99% of customer assets in offline cold storage after Binance lost $6.3 billion in an October 29 hack. Coinbase said the breach did not affect its systems or funds; a small share of assets remains in online hot wallets for withdrawals, while its Custody service holds all assets offline and separate on-chain. It splits private keys and can pause suspicious activity. Binance attackers compromised engineers through a tampered download and fake job interview, then used stolen credentials and an internal AI tool to move 233.46 million XRP from five hot wallets in four minutes. Binance froze or intercepted about $2.85 billion, but unauthorized transfers continued for nearly four hours.