Hackers stole $150 million in cryptocurrency from the crypto exchange BitMart by exploiting a vulnerability in the exchange's hot wallets. Hot wallets are more vulnerable to hacks than cold wallets, but they are also more convenient to use. Crypto exchanges can protect themselves from hacks by implementing strong security measures, keeping their hot wallets to a minimum, and regularly auditing their security systems. The BitMart hack is a reminder that crypto exchanges are not immune to hacks. Investors should carefully consider the security measures of an exchange before depositing their cryptocurrency.