[aiCeivi9]

The steps are same for PoW & PoS:

1. Cashout - for example send coins to an exchange, sell them for other crypto, withdraw everything

2. Flood the network with transaction where your coin was transferred to your other wallet instead of exchange

3. There are two conflicting transactions, you want the network to select the one where coins stay in your hands. For PoW that requires 50%+ of CPU power, for PoS it requires to have significant % of all coins.

It is like brute forcing card chargeback - merchant had your money and they are gone and he can't do much about it. It makes exchanges more likely a target of double spending attack than the source. I guess higher deposit/withdraw delays&fees would make PoS attacks unprofitable.